Access and support catheter methods of use

ABSTRACT

Described herein are methods of using bend-limited catheters that are freely bendable at angles greater than the locking bend angle, e.g., when the bend radius is less than the locking bend radius. The device will limit or prevent bending beyond the locking bend angle.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication No. 62/629,069, titled “SUPPORTIVE CATHETER,” filed on Feb.11, 2018 and U.S. Provisional Patent Application No. 62/651,049, titled“SUPPORTIVE CATHETER,” filed on Mar. 30, 2018, each of which is hereinincorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

Catheter devices and methods for using them for insertion into the bodyduring medical procedures that are loose and flexible up to apredetermined locking angle that avoid kinking, prolapse and kickback.More particularly, described herein are flexible tubular catheters,including guide catheters and balloon catheters, guide catheters, druginfusion catheters, and the like, as well as methods of using and makingthem.

BACKGROUND

Catheters are tubular devices that may be used in the medical field fornumerous applications. It is generally desirable to obtain a maximumtorsional rigidity while retaining a satisfactory longitudinalflexibility and stiffness without kinking. These features may allow theorientation of the catheter to be manipulated so that the catheter canbe guided through small body vessels and cavities. These features mayalso prevent any kinking, and may provide the catheter with enough“push” or stiffness so as to prevent the catheter from wrinkling orfolding back on itself during this process. The specific nature of thesecharacteristics may vary depending on the specific application for whichthe catheter is being used. It may also be beneficial to provide arelatively small outside diameter and a lumen or an inside diameter aslarge as possible.

Catheters (with our without guide wires) may be used both as adiagnostic tool and in the treatment of diseases. One such diagnosticprocedure is cardiac catheterization which is a widely performedprocedure, being used for assessment of coronary artery disease. Otheruses are neurologic uses, radiologic uses, electrophysiologic uses,peripheral vascular uses, etc. One example of a treatment use is the useof balloon catheters in dilation procedures to treat coronary disease.Dilation procedures rely upon the use of a catheter for injection ofcontrast and delivery of guidewires and dilation catheters to thecoronary artery or other arteries. An example of the use of guide wiresis for Percutaneous Transluminal Coronary Angioplasty (PTCA) balloonsand for guiding diagnostic catheters through the arteries and to bodyorgans.

The catheters and guide wires used in these and other procedures musthave excellent torque characteristics, and must have the requisiteflexibility. In addition, it is important that catheters and guidewiresprovide sufficient longitudinal support for “pushing” of items throughthe arteries and other vessels such as when feeding the balloon portionof an angioplasty catheter through the arteries. Unless there issufficient stiffness, the catheter or guidewire will wrinkle or foldback on itself. Catheters should ideally have sufficient torque suchthat they do not buckle when being manipulated. Flexibility may beimportant so that the catheter can be manipulated into the varyingarterial branches encountered by the catheter.

Prior art catheters are typically made of flexible materials which arereinforced such that the resulting composite catheter approximates thedesired characteristics. In alternative approaches, guide wires are usedin conjunction with catheters to assist in manipulating and moving thecatheters through the arterial system in the body. Described herein arecatheters are highly flexible, while maintaining stability, preventingkickback and resisting prolapse and kinking.

SUMMARY OF THE DISCLOSURE

Described herein are bend-limited catheter apparatuses, e.g., devicesand systems, and methods of using them to perform a medical procedure.In general, the apparatuses described herein may include an elongatetubular body that includes one or more cut-out kerfs forming a patternof interlocking teeth that are arranged in rings (and/or one or morespiral patterns) around the perimeter of the elongate tubular body. Thepattern of interlocking teeth is configured, as described in greaterdetail herein, to provide the catheter with a high degree of flexibilityin bending, while permitting the device to lock at a locking diameter(or locking radius) when the relevant portion of the catheter bends to aminimum locking angle, or minimum locking angle per unit lengthcorresponding to the locking diameter, beyond which no further bendingis permitted. The cut-out kerf(s) may be sealed, e.g., by a compressiblematerial, such as a polymer, so that the catheter walls are fluid-tight,which may be referred to herein as a jacket or seal.

Generally, the bend-limited catheters described herein may be configuredto be highly flexibility until bent to the locking bend angle. In somevariations the portion(s) of the catheter including the pattern ofinterlocking teeth arranged radially around the perimeter and extendingdown the length of the tubular body may be loose, or floppy, wheninitially bending from the straight, unbent configuration until bent tothe locking bend angle, preventing further bending. In addition, thebend-limited catheters described herein may be thin (e.g., have a smallwall thickness) and the pattern of interlocking teeth may be configuredso that the catheters are highly smooth, while remaining lockable andhighly flexible.

These features (e.g., smoothness, lockability and flexibility) may beachieved in a thin-walled, e.g., metal or rigid polymeric, tube byforming the pattern of interlocking teeth in which each tooth hasdimensions, including tooth angle, tooth height, tooth spacing (e.g.,pitch, such as pitch/catheter diameter), and tooth number that increasesmoothness, permitting a high level of flexibility without reducing thestrength of the catheter under bending (including compressive) loads.The catheters described herein typically have an outer and innersmoothness that permits the use of inserted devices without riskingsnagging or cutting. Smoothness of these bend-limited catheters may be,at least in part, a function of the low pitch angle (and small backboneregion), as well as the number of teeth; a larger number of smaller,and/or shorter teeth may provide a smoother surface. Unfortunately,smaller number and/or heights for the interlocking teeth typicallyresults in lower flexibility and may decrease the strength of thecatheter. In general, the larger the pitch, or the spacing betweenadjacent rows/spirals of interlocking teeth along the length of thecatheter, which may include the height of the teeth in the length of thecatheter and the backbone spacing between adjacent rows/spirals, maygenerally increase flexibility while reducing smoothness (particularlywhere the contribution of backbone spacing to the pitch is small, e.g.,less than 50%) and may permit a larger locking diameter. Thus, describedherein are ranges of values that may balance these often conflictingproperties to provide bend-limited catheters that may be used for avariety of medical uses, including neurovascular and cardiovascularuses.

Any of the bend-limited catheters described herein, which may bereferred to herein as bend-limited catheter apparatuses or bend-limitedcatheter devices, may include a tubular body having one or more cut-outkerfs forming a pattern of interlocking and alternating teeth extendingaround the tubular body, wherein each tooth of the interlocking andalternating teeth comprises a head region that is wider than a baseregion, arranged so that the head regions alternate with base regionsradially around the tubular body, so that the first region bends in adirection out of a long axis of the catheter device up to a lockingradius, beyond which the tubular body does not allow further bending inthe direction. The pattern of interlocking and alternating teeth mayextend along the entire length of the tubular body, or just along one ormore regions (e.g., a first region, a second region, a third region,etc.) of the length of the tubular body. In variation in which multipleregions along the length of the tubular body include a pattern ofinterlocking and alternating teeth, the same pattern may be used ordifferent patterns may be used, which may provide different regionshaving different smoothnesses, flexibilities, and/or locking bendangle(s). When the bend-limited catheter includes multiple regions alongthe length of the tubular body are used, these regions may beimmediately adjacent to each other or they may be separated from eachother by a transition region and/or by a region that does not includeinterlocking and alternating teeth. A transition region may have apattern of interlocking and alternating teeth that transitions betweenthe pattern of interlocking and alternating teeth in theproximally-located region of the catheter and the pattern ofinterlocking and alternating teeth in the distally-located region of thecatheter. The transition may be gradual or abrupt.

Any of the catheters described herein may include a sleeve, seal, skin,cover, sheath, or the like that may comprise a sealing material, whichmay be a compressible material. extending across the cut-out kerf. Forexample, the sealing material may be laminated to the rigid tubular body(e.g., to an inner surface, an outer surface, or both). In somevariations the sealing material is positioned between the inner andouter surfaces of the tubular body, including within the cut-out kerf.Any appropriate sealing material may be used. The sealing material maybe a polymeric material. In particular, the sealing material may be athin layer, coating, film, etc. (e.g., about 0.01 inches or less thick,about 0.009 inches or less, about 0.008 inches or less, about 0.007inches or less, about 0.006 inches or less, about 0.005 inches or less,about 0.004 inches or less, about 0.003 inches or less, about 0.002inches or less, about 0.001 inches or less, etc.). The sealing materialmay be a material having a relatively high (e.g., Shore A) durometer,such as materials having a shore A durometer of about 60 or greater,about 65 or greater, about 70 or greater, about 75 or greater, about 80or greater, etc.

The interlocking and alternating teeth of the bend-limited catheterdevices described herein may be any appropriate shape or variety ofshapes, such as keystone shapes, a mushroom shapes, and a T-shapes. Inparticular, the alternating teeth may be keystone shapes. A keystoneshape generally has a larger top region, which may be flat or flattened,with sharp or rounded edges and sides that extend at an angle relativeto the top (one example of a tooth angle) to a base, so that the basediameter is narrower than the top. As illustrated herein the base regionof a tooth forms the top region of the alternate next tooth. Thus, thepattern of interlocking and alternating teeth may be a pattern ofinterlocking and alternating keystone-shaped teeth.

For example, a bend-limited catheter device having a length extending ina long axis, may include: a tubular body having a first region of one ormore cut-out kerfs forming a pattern of interlocking and alternatingkeystone-shaped teeth extending around the tubular body, wherein eachtooth of the interlocking and alternating teeth comprises a head regionthat is wider than a base region, arranged so that the head regionsalternate with base regions radially around the tubular body, so thatthe first region bends freely in a direction out of a long axis of thecatheter device with a lateral stiffness that is less than 100 grams upto a locking radius, beyond which the tubular body does not allowfurther bending in the direction; and a sealing material extendingacross the cut-out kerf.

In any of the catheters described herein, the expansion between adjacentteeth of the interlocking and alternating teeth may be greater than adiameter of the one or more cut-out kerfs. Expansion between adjacentteeth may occur because the side of the teeth, e.g., in akeystone-shaped tooth, the angled, lateral sides of the keystone shapeextending between the top and base, slide relative to each other inapproximately the long axis of the catheter (e.g., distal to proximal).The length of the lateral sides along which this sliding occurs may bemaximized in some variations (e.g., may be X % or greater than theheight of the tooth, where X is 20, 25, 30, 25, 40, 50, etc.). Forexample, the pattern of interlocking and alternating teeth may beconfigured to expand from a compressed elongate length by between about0.005 inches and 0.085 inches per every 0.1 inch of the length of thepattern. In some variations (or regions) having a kerf diameter of about0.001 inches, the pattern of interlocking and alternating teeth may beconfigured to expand by about 0.002″ for each mating set of teeth; insome variation (or regions), the pattern of interlocking and alternatingteeth may be configured to expand by about 0.005″ for each mating set ofteeth (e.g., between 0.002 inches and 0.010 inches).

The pattern of interlocking and alternating teeth may include anyappropriate number of teeth per revolution around the diameter of thetubular body that can be fit with the pitch and dimensions describedherein. As mentioned above, it may be beneficial to balance the numberof smaller teeth (increasing flexibility at the possible expense ofminimum bend diameter) with larger teeth (decreasing flexibility butincreasing minimum bend diameter). For example, the tubular body maycomprise a minimum of 18 teeth per revolution around the diameter of thetubular body (or between 6-70 teeth per revolution, between 12-65 teethper revolution, between 15-62 teeth per revolution, between 18-60 teethper revolution, between 20-60 teeth per revolution, 15 or moreteeth/revolution, 18 or more teeth/revolution, 20 or moreteeth/revolution, 22 or more teeth/revolution, etc.

In any of the catheters described herein, the ratio of the pitch of theteeth to the tubular body diameter may be between 0.09 and 0.90 (e.g.,between 0.1 and 0.9, between 0.12 and 0.85, between 0.10 and 0.50,etc.). The pitch may refer to the distance between adjacent rows ofinterlocking and alternating teeth along the long axis of the tubularbody, including the height of the teeth; for example, the pitch may bethe height of the teeth (the distance between the head region and thebase region) and the backbone distance before the start of the next loopof interlocking teeth in the long axis. The diameter of the tubular bodymay be measured transverse to the portion of the tubular body (e.g.,transverse to the long axis of the tubular body) at or around thelocation of the interlocking teeth defining the pitch measurement. Asmentioned above, in some variations the pitch may include both theheight of the teeth and the backbone portion separating long-axisadjacent teeth; the portion of the backbone in the pitch may be, e.g.,60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% orless, 30% or less, 25% or less, 20% or less, etc. and may have a minimumof 2%, 5%, 7%, 10%, etc. (e.g., between about 2% and 50%, between about5%-55%, 7.5%-50%, etc.).

In general, the pattern of interlocking and alternating teeth may beconfigured so that the tooth angle is within a range that permits theexpansion area of the catheter device to be within predefined limits,while permitting increased flexibility, smoothness and a locking anglewithin a defined range. For example, the teeth of the pattern ofinterlocking and alternating teeth may form a tooth angle between a lineextending through a width of the head region (or in keystone-shapedteeth the flat or flattened top) and a line extending from the headregion and the base region (e.g., the sides of the keystone-shapedteeth) of between about 40 degrees and about 89 degrees; in somevariations between about 40 degrees and about 65 degrees (e.g., betweenabout 40 and about 60 degrees, etc., between about 45 and about 65degrees, between about 45-63 degrees, etc.), in some variations betweenabout 66 and about 87 degrees (e.g., between about 68 and about 84degrees, between about 66 and about 82 degrees, etc.).

The tubular body may be formed of generally inflexible, e.g., rigid,material. For example, in some variations, the tubular body may be arigid material such as one or more of: steel, tungsten, and Nitinol. Thetubular body may therefore be cut (e.g., laser cut) to form the one ormore cut-out kerfs forming a pattern of interlocking and alternatingteeth. The cut-out kerf may have any appropriate diameter, includingconstant or near-constant (within +/−2%, 5%, 7.5%, etc.) diameter alongits length(s), or it may vary. In some variations, the kerf has adiameter of between about 0.005 inches and 0.0005 inches (e.g., about0.001 inches, about 0.002 inches, about 0.0009 inches, etc.).

The pattern of interlocking and alternating teeth may generally have aratio of the bend radius to a diameter of the tubular body of betweenabout 1 and 25 (e.g., between about 1.5 to 22.5, etc.). The ration ofthe bend radius of a region of the tubular body including the pattern ofinterlocking and alternating teeth to the diameter of the kerf formingthe pattern may be between about 100 and 2100 (e.g., between about 120and 2000, 2100 or less, 2050 or less, 2000 or less, 1950 or less, etc.).

Any of the catheter devices described herein may include one or moreballoons, e.g., inflatable balloon elements, along the length of thedevice. For example, any of these catheter devices may include aninflatable balloon on the catheter, including, but not limited to, at ornear a distal end of the catheter.

In general, the bend-limited catheter devices described herein may beconfigured to have a locking radius, as mentioned above, that is betweenabout 0.1 cm and about 40 cm, e.g., between about 0.2 cm and about 35cm, between about 0.2 cm and 30 cm, between about 0.3 cm and about 28cm, between about 0.4 cm and about 27 cm, between about 0.5 cm and about26 cm, etc.

For example, a bend-limited catheter device having a length extending ina long axis, may include: a tubular body having a first region of one ormore cut-out kerfs forming a pattern of interlocking and alternatingkeystone-shaped teeth extending around the tubular body, wherein eachtooth of the interlocking and alternating keystone-shaped teethcomprises a head region that is wider than a base region, arranged sothat the head regions alternate with base regions radially around thetubular body, so that the first region bends in a direction out of along axis of the catheter device up to a locking radius of between 0.2cm and 30 cm, beyond which the tubular body does not allow furtherbending in the direction, wherein each tooth of the interlocking andalternating teeth form a tooth angle between a line extending through awidth of the head region and a line extending from the head region andthe base region that is between 40 and 84 degrees, further wherein thepitch to tubular body diameter ratio of the first region is between 0.09and 0.90, wherein pitch is a distance between adjacent rows ofinterlocking and alternating teeth along the long axis of the tubularbody; and a sealing material extending across the cut-out kerf.

Any of the catheters, and systems including them, described herein mayinclude a plurality of different regions that may be configured to havedifferent maximum bend angles (e.g., locking angles), flexibility and/orsmoothness. In particular, it may be particularly helpful to providecatheters having different regions of cut-out kerfs forming one or morepatterns of interlocking and alternating teeth extending around thetubular body that have different flexibilities and different bend anglesin a distal region as compared to a proximal region. For example, abend-limited catheter as described herein may include one or morecut-out kerfs forming a pattern of interlocking and alternating teethextending around the tubular body that is/are configured so that adistal region of the catheter has a higher tooth angle and lower ratioof pitch to tube diameter as compared to a more proximal region of thecatheter (which therefore has a lower tooth angle and a high ratio ofpitch to tube diameter). This configuration may have a distal regionhaving a smaller bend diameter/bend radius as compared to a distalregion having a larger bend diameter/bend radius (e.g., locking radius).The second region may correspond to a region within the anatomy of apatient in which the catheter is configured to be inserted; the minimumbend angle or locking angle may correspond to the aortic region of theanatomy, where it may be desirable to prevent excessive bending orbucking.

For example in some variations, the catheter may be formed of a tubularbody that includes one or more cut-out kerfs forming a pattern ofinterlocking and alternating teeth extending around the tubular body andhas a, e.g., first, distal region (e.g., at or near the distal end ofthe catheter), extending for about 2 cm or more (e.g., 2.5 cm or more, 3cm or more, 5 cm or more, 7.5 cm or more, 8 cm or more, 10 cm or more,15 cm or more, etc.) and a second region proximal to the distal regionthat extends for 2 cm or more (e.g., 2.5 cm or more, 3 cm or more, 5 cmor more, 7.5 cm or more, 8 cm or more, 10 cm or more, 15 cm or more, 25cm or more, etc.). The teeth of the first region (on average orindividually) may have a larger tooth angle than the teeth of the secondregion (on average or individual). For example, the teeth of the firstregion may have a tooth angle (in some variations an average toothangle, in some variations a maximum tooth angle, in some variations aminimum tooth angle, in some variations a median tooth angle, etc.) ofbetween about 61 degrees to 84 degrees (e.g., 63 degrees to 82 degrees,64 degrees to 84 degrees, etc., 61 degrees or more, 62 degrees or more,63 degrees or more, 64 degrees or more, 65 degrees or more, 66 degreesor more, etc.). The teeth of the second region may have a tooth angle(in some variations an average tooth angle, in some variations a maximumtooth angle, in some variations a minimum tooth angle, in somevariations a median tooth angle, etc.) of between about 30 degrees to 64degrees, between about 35 degrees to 62 degrees, between about 40degrees to 60 degrees, about 58 degrees, etc.). At the lower tooth angle(e.g., about 45 degrees, about 48 degrees, about 50 degrees, about 55degrees, about 58 degrees, etc.) with a 0.001″ kerf, the device may beconfigured to have an additional linear expansion of 0.002″ for eachmating set of teeth. This configuration may be particularly helpful whenthe catheter is configured so that the second (more proximal region) hasa larger locking diameter as compared to the distal end region (e.g.,which may keep the catheter from prolapsing). At the larger tooth anglesof the distal end of the device, e.g., having a tooth angle of about 78degrees, with a 0.001″ kerf, the distal region of the device has anadditional linear expansion of about 0.005″ for each mating set ofteeth, leading to greater flexibility at the distal end region. Althoughthe tooth angle of the distal end of the device may be as low as 40 oreven 30 degrees in some variations, as these angles get smaller, lessteeth may fit around the diameter, which, while increasing smoothness,may weaken the device and allow more loads to be concentrated onindividual teeth potentially weakening the construct. Thus, in general,lower amounts of expansion between teeth of the cut-out kerf pattern mayimprove surface smoothness. Higher tooth angles may therefore be bestutilized at the distal end of the catheter. As the tooth angle getshigher, the tooth height may need to increase to have a reasonableamount of tooth engagement (e.g., along the engagement surface). As theangle gets even larger, the tooth height may increase more, which mayincreases the required pitch and minimum bend diameter. Also, the teethmay be more likely to wedge together as this angle gets larger.

The pitch distance may reflect the tooth height, and may impactsmoothness and flexibility. As the pitch gets smaller, the tooth heightmay be reduced; reducing the pitch typically requires a smaller toothheight. Higher pitch distances may therefore be used in regions having alarger bend radius/bend diameter (the bend diameter is twice the bendradius). Fewer teeth per unit length of the catheter may increase theminimum bend diameter. Similarly, lower pitch distances may be bestutilized in regions having smaller bend radius/bend diameters, e.g.,towards the distal end of the catheter. Lower pitch distances allowpacking more teeth per unit length and may permit greater linearexpansion and smaller bend radii. Although the relative expansionbetween each tooth may be greater due to higher tooth angles, the teethmay be made shorter (resulting in a smaller pitch) to help keep thesurfaces smooth.

The normalized ratio of pitch to tube diameter may be used to adjust theproperties of a catheter or region of a catheter to have desiredproperties. For example, a pitch to tube diameter of between about 0.009to about 0.20 (e.g., about 0.10, about 0.12, about 0.13, about 0.15,etc.) at the distal end of the catheter may result in a highflexibility, and a larger pitch to tube diameter ratio (e.g., betweenabout 0.30 to 0.90, about 0.31 to about 0.80, about 0.33 to about 0.70,about 0.33 to about 0.50, etc.) at the more proximal region may increasethe minimum bend radius and prevent prolapse in larger-diameter vesselregions (or vessel intersection regions, such as aortic regions).

For example, a bend-limited catheter device having a length extending ina long axis, the device comprising: a tubular body having one or morecut-out kerfs forming a pattern of interlocking and alternating teethextending around the tubular body, the pattern repeating from a distalregion to a proximal region of the length of the tubular body, whereineach tooth of the interlocking and alternating teeth comprises a headregion that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body, sothat the catheter bends in a direction out of a long axis of thecatheter device up to a locking radius, beyond which the tubular bodydoes not allow further bending in the direction; wherein each tooth ofthe interlocking and alternating teeth form a tooth angle between a lineextending through a width of the head region and a line extending fromthe head region and the base region; further wherein a proximal portionof the pattern of interlocking and alternating teeth comprises teethhaving an average tooth angle that is less than an average tooth angleof a more distal portion of the pattern of interlocking and alternatingteeth.

For example, a bend-limited catheter device having a length extending ina long axis may include: a tubular body having one or more cut-out kerfsforming a pattern of interlocking and alternating teeth extending aroundthe tubular body, the pattern repeating from a distal region to aproximal region of the length of the tubular body, wherein each tooth ofthe interlocking and alternating teeth comprises a head region that iswider than a base region, arranged so that the head regions alternatewith base regions radially around the tubular body, so that the catheterbends in a direction out of a long axis of the catheter device up to alocking radius, beyond which the tubular body does not allow furtherbending in the direction; wherein each tooth of the interlocking andalternating teeth form a tooth angle between a line extending through awidth of the head region and a line extending from the head region andthe base region; further wherein a distal portion of the pattern ofinterlocking and alternating teeth comprises teeth having an averagetooth angle that is greater than an average tooth angle of a moreproximal portion of the pattern of interlocking and alternating teeth;and wherein the distal portion of the pattern of interlocking andalternating teeth has a pitch to tubular body diameter ratio that isless than the pitch to tubular body diameter ratio of the more proximalportion of the pattern of interlocking and alternating teeth, whereinthe pitch is a distance between adjacent rows of interlocking andalternating teeth along the long axis of the tubular body.

For example, a bend-limited catheter device having a length extending ina long axis, the device comprising: a tubular body having one or morecut-out kerfs forming a pattern of interlocking and alternatingkeystone-shaped teeth extending around the tubular body, the patternrepeating from a distal region to a proximal region of the length of thetubular body, wherein each keystone-shaped tooth of the interlocking andalternating keystone-shaped teeth comprises a head region that is widerthan a base region, arranged so that the head regions alternate withbase regions radially around the tubular body, so that the catheterbends in a direction out of a long axis of the catheter device up to alocking radius; wherein each keystone-shaped tooth of the interlockingand alternating keystone-shaped teeth form a tooth angle between a lineextending through a width of the head region and a line extending fromthe head region and the base region; further wherein a distal portion ofthe pattern of interlocking and alternating keystone-shaped teeth thatextends more than 2 cm along the length of the long axis compriseskeystone-shaped teeth having a tooth angle that is between 61-84degrees, and a proximal portion of the pattern of interlocking andalternating keystone-shaped teeth that extends more than 2 cm along thelength of the long axis comprises keystone-shaped teeth having a toothangle that is between 30 to 60 degrees; and wherein the distal portionof the pattern of interlocking and alternating keystone-shaped teeth hasa pitch to tubular body diameter ratio that is between 0.09 and 0.30 anda pitch to tubular body diameter ratio of the more proximal portion ofthe pattern of interlocking and alternating keystone-shaped teeth isbetween 0.30 and 0.90, wherein pitch is a distance between adjacent rowsof interlocking and alternating teeth along the long axis of the tubularbody and the tubular body diameter is the diameter of the tubular bodytransverse to the adjacent rows of interlocking and alternating teeth.

The distal portion of the pattern of interlocking and alternating teethmay be configured to expand from a compressed elongate length by betweenabout 0.005 inches and 0.085 inches per every 0.1 inch of the length ofthe pattern. Further, the proximal portion may be configured to expandfrom a compressed elongate length by less than the distal portion of thepattern of interlocking and alternating teeth.

The distal portion may be immediately adjacent to the proximal portionor may be separated from the proximal portion by a spacing region (e.g.,a transition region). One or more additional portions or region, havingdifferent properties, including different pattern(s) of interlocking andalternating teeth, may be on the elongate body, including proximal tothe proximal region.

As mentioned above, the distal portion of the pattern of interlockingand alternating keystone-shaped teeth may extends 2 cm or more along thelength of the long axis (e.g., about 4 cm or more, about 5 cm or more,about 6 cm or more, about 10 cm or more, etc.). The proximal portion ofthe pattern of interlocking and alternating keystone-shaped teeth mayextend 2 cm or more (e.g., 3 cm or more, 4 cm or more, 5 cm or more, 10cm or more, etc.) the length of the long axis.

The distal portion of the pattern of interlocking and alternating teethmay have a pitch to tubular body diameter ratio that is between, e.g.,0.09 and 0.30 and a pitch to tubular body diameter ratio of the moreproximal portion of the pattern of interlocking and alternatingkeystone-shaped teeth that is between, e.g., 0.30 and 0.90.

In some variations, the distal portion of the pattern of interlockingand alternating teeth may comprise 20 or more teeth per revolutionaround the diameter of the tubular body, and wherein the proximalportion of the pattern of interlocking and alternating teeth maycomprise between 6-20 teeth per revolution around the diameter of thetubular body.

As mentioned above, the teeth may each form a keystone shape. The one ormore cut-out kerfs may have a diameter of between 0.0005 and 0.002inches (e.g., about 0.001 inches). The tubular body may comprises one ormore of: steel, tungsten, and Nitinol.

Any of these devices may include a sealing material extending across thecut-out kerf, e.g., laminated to the inside and/or outside of the rigidtubular body. Any of these devices may include an inflatable balloon onthe catheter.

The locking radius of the distal portion of the pattern of interlockingand alternating teeth may be more than 15% smaller than the lockingradius of the proximal portion of the pattern of interlocking andalternating teeth. For example, the locking radius of the proximalportion of the pattern of interlocking and alternating teeth may bebetween 15 cm and 35 cm.

Also described herein are methods of using any of the devices describedherein. In general, these methods typically include inserting thecatheters using a guide devices (e.g., guidewire or guide catheter)within the lumen of the bend-limited catheter, which may providesufficient stiffness so that it can be driven distally into the patient.The high flexibility of the catheter, particularly the distal endintermediate regions) may provide a high degree of tracking over theguidewire/guide catheter. Once in position, the guidance device may beremoved from the lumen of the catheter, and the catheter may be advanceddistally; because it is so ‘floppy’, particularly at the distal andintermediate region, the catheter will curve within (and in some casesagainst the vessel walls) and lock in place, preventing the distal endof the catheter from moving much. The catheter may bend only to thelocking bend angle, at which point it will lock in position, preventingbuckling and/or kickback and/or prolapse within the vessel. Thereafter,one or more tools (other catheters, scopes, etc.) may be deliveredthrough the catheter to the target tissue at the distal end and forceapplied against the catheter, even in compression, may not substantiallymove the distal end of the catheter and/or kink or prolapse thecatheter.

Thus, a method of providing catheter access to a target region of avessel within a patient's body using any of the apparatuses describedherein may include: advancing a bend-limited catheter device over aguidewire or guide catheter into the vessel until the distal end of thebend-limited catheter device is adjacent to the target region, whereinthe bend-limited catheter comprises a tubular body having one or morecut-out kerfs forming a pattern of interlocking and alternating teethextending around the tubular body, wherein each tooth of theinterlocking and alternating teeth comprises a head region that is widerthan a base region, arranged so that the head regions alternate withbase regions radially around the tubular body, so that the tubular bodybends freely in a direction out of a long axis of the catheter device upto a locking radius, beyond which the tubular body does not allowfurther bending in the direction; removing the guidewire at leastpartially out of the bend-limited catheter; and advancing the proximalend of the bend-limited catheter so that the bend-limited catheter lockswithin the vessel by bending to the locking radius without moving thedistal end of the bend-limited catheter from the target region. Any ofthese methods may include positioning the guidewire or guide catheterinto the vessel. Any of these methods may also include inserting atreatment device (e.g., scope, thrombecomy apparatus, stent, etc.)through the bend-limited catheter to the target region.

For example, described herein are methods of providing catheter accessto a target region of a vessel within a patient's body, the methodcomprising: advancing a bend-limited catheter device over a guidewire orguide catheter into the vessel until the distal end of the bend-limitedcatheter device is adjacent to the target region, wherein thebend-limited catheter comprises a tubular body having a first region ofone or more cut-out kerfs forming a pattern of interlocking andalternating keystone-shaped teeth extending around the tubular body,wherein each tooth of the interlocking and alternating keystone-shapedteeth comprises a head region that is wider than a base region, arrangedso that the head regions alternate with base regions radially around thetubular body, so that the first region bends freely in a direction outof a long axis of the catheter device up to a locking radius, beyondwhich the tubular body does not allow further bending in the direction;removing the guidewire at least partially out of the bend-limitedcatheter; and advancing the proximal end of the bend-limited catheter sothat the bend-limited catheter locks within the vessel by bending thefirst region to the locking radius without moving the distal end of thebend-limited catheter from the target region.

For example, a method of providing catheter access to a target region ofa vessel within a patient's body may comprise: advancing a bend-limitedcatheter device over a guidewire or guide catheter into the vessel untilthe distal end of the bend-limited catheter device is adjacent to thetarget region, wherein the bend-limited catheter comprises a tubularbody having a first region of one or more cut-out kerfs forming apattern of interlocking and alternating teeth extending around thetubular body, wherein each tooth of the interlocking and alternatingteeth comprises a head region that is wider than a base region, arrangedso that the head regions alternate with base regions radially around thetubular body, so that the first region bends freely in a direction outof a long axis of the catheter device up to a locking radius, beyondwhich the tubular body does not allow further bending in the direction;removing the guidewire at least partially out of the bend-limitedcatheter; and advancing the proximal end of the bend-limited catheter sothat the bend-limited catheter locks within the vessel by bending thefirst region to the locking radius without moving the distal end of thebend-limited catheter from the target region, wherein the first regionof the tubular body of the bend-limited catheter bends freely with alateral stiffness for a distal 10 cm of the catheter that is less than50 grams in a direction out of a long axis of the catheter device up tothe locking radius.

The tubular body of the bend-limited catheter may bend freely in adirection out of a long axis of the catheter device up to the lockingradius of between, e.g., about 0.2 and 32 cm (e.g., about 0.2 and 30 cm,about 0.3 cm and about 29 cm, about 0.3 and about 28 cm, about 0.4 andabout 27 cm, about 0.4 and about 26 cm, etc.).

The tubular body of the bend-limited catheter may bend freely with alateral stiffness for a distal 10 cm (or more) of the catheter that is100 grams or less (e.g., 150 g or less, 100 g or less, 75 g or less, 50g or less, etc.) in a direction out of a long axis of the catheterdevice up to the locking radius. For example, the lateral stiffness ofthe distal 10 cm or more of the catheter may be 125 g or more (e.g., 150g or greater, 175 g or greater, 200 g or greater, 250 g or greater, 275g or greater, 300 g or greater, 325 g or greater, 350 g or greater,etc.) when the catheter is bent beyond the locking radius.

The pattern of interlocking and alternating teeth and the cut-out kerfmay be configured so that the tubular body expands in the long axis froma compressed length to a maximally expanded length by between about0.005 inches per every 0.1 inch of the length of the pattern ofinterlocking and alternating teeth and 0.085 inches per every 0.1 inchof the length of the pattern of interlocking and alternating teeth, asdescribed above.

In any of the devices and methods described herein, the pattern ofinterlocking and alternating teeth may extend helically around thetubular body; alternatively the pattern may comprise a plurality ofadjacent rings that extend around the tubular body.

Any of these methods may include compressing a sealing materialextending across the cut-out kerf when advancing the proximal end of thebend-limited catheter to bend to the locking radius. The sealingmaterial may prevent fluid from passing between the outside and theinside of the tubular member. The sealing material may be laminated tothe rigid tubular body.

In some variations, as will be described in greater detail below, thebend-limited catheter may be a non-uniformly bend-limited catheter.Rotating the catheter from the proximal end may adjust the lockingradius of the catheter and/or may otherwise assist in locking thecatheter in position within the vessel.

Any of the methods described herein may include anchoring the distal endof the catheter near the target region. For example, the distal end maybe anchored in position by inflating a balloon on the catheter (e.g., ator near a distal end of the catheter. In some variations, the distal endof the catheter may be held in position securely even without a separateanchor, as described above.

In general, the pattern of interlocking and alternating teeth maycomprise a plurality of keystone-shaped interlocking and alternatingteeth.

The bend-limited catheter apparatuses described herein may thereforefreely permit bending of the catheter with very little (e.g.,negligible) force, even when jacketed, until the catheter is bent to thelocking bend angle, beyond which it is locked, and prevents bending. Asmentioned above, in some variations, the pattern of interlocking teethformed by the cut-out kerf(s) is configured so that one or moredirections of bending has a different (e.g., smaller or larger) lockingdiameter and therefore locking bend angle.

For example, a non-uniformly bend-limited catheter device having alength extending in a long axis may include: a tubular body formed of arigid material having one or more cut-out kerfs forming a pattern ofinterlocking and alternating teeth extending around the tubular body,wherein each tooth of the interlocking and alternating teeth eachcomprise a head region that is wider than a base region, arranged sothat the head regions alternate with base regions radially around thetubular body, so that the tubular body bends freely out of the long axisup to a locking radius, beyond which the tubular body does not allowfurther bending; wherein each tooth of the interlocking and alternatingteeth form a tooth angle between a line extending through a width of thehead region and a line extending from the head region and the baseregion, further wherein the tooth angles of the interlocking andalternating teeth vary radially around the tubular body so that thelocking radius of the potion of the length of the tubular body variesradially around the tubular body.

Any of the catheter features described above may be used as part of anon-uniformly bend-limited catheter.

In some variations, the tooth angles of the non-uniformly bend-limitedcatheter may vary between 10 degrees and 89 degrees (e.g., between 30and 87 degrees, between 40 and 84 degrees, etc.). The pattern ofinterlocking and alternating teeth and the cut-out kerf may beconfigured so that the tubular body expands in the long axis from acompressed length to a maximally expanded length by between about 0.005inches per every 0.1 inch of the length of the pattern of interlockingand alternating teeth and 0.085 inches per every 0.1 inch of the lengthof the pattern of interlocking and alternating teeth.

In any of these variations, the distance between the head region and thebase region of the teeth may vary radially around the tubular body.

As mentioned above, the tubular body may comprise a metal or rigidpolymeric material (e.g., one or more of: steel, tungsten, and Nitinol).The pattern of interlocking and alternating teeth may extend helicallyaround the tubular body and/or may include a plurality of adjacent ringsarranged along the length of the tubular body. Any of these devices mayinclude a sealing material extending across the cut-out kerf, e.g.,laminated to an outer, inner or both surfaces of the rigid tubular body.The sealing material may have a Shore A durometer hardness of greaterthan 75 (e.g., between 80 and 100), but may be relatively thin(typically thinner than the thickness of the tubular body).

As mentioned above, the teeth may be keystone-shaped teeth (e.g., mayeach form a keystone shape). Alternatively, in some variations, theteeth may each form one of: a keystone shape, a mushroom shape, and aT-shape.

The locking radius may be between about 0.2 cm and 32 cm (e.g., betweenabout 0.2 cm and about 30 cm, between about 0.4 cm and about 29 cm,between about 0.5 cm and about 28 cm, etc.).

Any of the devices described herein may include a second region of thelength of the tubular body that comprises a second one or more cut-outkerfs forming a second pattern of interlocking and alternating teethextending around the tubular body, so that the second region of thetubular body bends freely out of the long axis up to a second lockingradius, beyond which the tubular body does not allow further bending.One or more additional regions may also be included. The second (ormore) regions may be non-uniformly bend-limited regions (e.g., having avarying bend angle and/or pitch), or they may be uniform bend-limitedregions.

The locking radius of the first region may be different from the secondlocking radius at one more positions radially around the tubular body.

For example, a non-uniformly bend-limited catheter device having anelongate length extending in a long axis may include: a tubular bodyformed of a rigid material having a cut-out kerf forming a pattern ofinterlocking and alternating teeth extending around the tubular body,wherein the interlocking and alternating teeth each comprise a headregion that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body;wherein the pattern of interlocking and alternating teeth and thecut-out kerf are configured so that the tubular body expands in the longaxis from a compressed length to a maximally expanded length by betweenabout 0.005 inches per every 0.1 inch of the length of the pattern ofinterlocking and alternating teeth and 0.085 inches per every 0.1 inchof the length of the pattern of interlocking and alternating teeth, sothat the tubular body bends freely out of the long axis up to a lockingradius, beyond which the tubular body does not allow further bending;further wherein each tooth of the interlocking and alternating teethform a tooth angle between a line extending through a width of the headregion and a line extending between the head region and the base region,wherein the tooth angles of the interlocking and alternating teeth varyradially around the perimeter of the tubular body, so that the lockingradius varies around the perimeter of the tubular body; and a sealingmaterial extending across the cut-out kerf.

As mentioned above, the distance between the head region and the baseregion of the teeth may vary radially around the tubular body. Thedevice may include a second region of the length of the tubular bodythat comprises a second one or more cut-out kerfs forming a secondpattern of interlocking and alternating teeth extending around thetubular body, so that the second region of the tubular body bends freelyout of the long axis up to a second locking radius, beyond which thetubular body does not allow further bending.

The first locking radius may be different from the second locking radiusat one more positions radially around the tubular body.

For example, a non-uniformly bend-limited catheter device having anelongate length extending in a long axis may include: a tubular bodyformed of a rigid material having a cut-out kerf forming a pattern ofinterlocking and alternating teeth extending around the tubular body,wherein the interlocking and alternating teeth each comprise a keystoneshape having a flattened head region that is wider than a base region,arranged so that the flattened head regions alternate with base regionsradially around the tubular body; wherein the pattern of interlockingand alternating teeth and the cut-out kerf are configured so that thetubular body bends freely out of the long axis up to a locking radius,beyond which the tubular body does not allow further bending; furtherwherein each tooth of the interlocking and alternating teeth form atooth angle between a line extending through a width of the flattenedhead region and a line extending between the flattened head region andthe base region, wherein the tooth angles of the interlocking andalternating teeth vary radially around the perimeter of the tubularbody, so that the locking radius varies around the perimeter of thetubular body; and a sealing material extending across the cut-out kerf.

Also described herein are methods of providing catheter access to atarget region of a vessel within a patient's body using any of thenon-uniformly bend-limited catheters described above. For example, amethod may include any of the steps described above for use with abend-limited catheter but may further include rotating the proximal endof the catheter before or during the application of force to advance theproximal end of the catheter after removing the guide wire/guidecatheter. This may allow the user to select or otherwise control thebend angle of the catheter apparatus in the lumen of the patient's bodyby orienting the non-uniformly bend-limited catheter so that the devicepreferentially bends in the selected direction out of the long axis(where the locking angle varies along the radial orientation of thedevice). The user may feel, via tactile feedback, the locking positionof the catheter within the vessel, e.g., by feeling resistance tobending when advancing the catheter distally, as described.

For example, a method may include advancing a non-uniformly bend-limitedcatheter device over a guidewire or guide catheter into the vessel untilthe distal end of the bend-limited catheter device is adjacent to thetarget region, wherein the non-uniformly bend-limited catheter comprisesa tubular body having one or more cut-out kerfs forming a pattern ofinterlocking and alternating teeth extending around the tubular body,wherein each tooth of the interlocking and alternating teeth comprises ahead region that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body, sothat the tubular body bends in a direction out of a long axis of thecatheter device up to a locking radius, beyond which the tubular bodydoes not allow further bending in the direction; rotating thebend-limited catheter to adjust the locking radius; removing theguidewire at least partially out of the bend-limited catheter; andadvancing the proximal end of the bend-limited catheter so that thebend-limited catheter locks within the vessel by bending to the lockingradius without moving the distal end of the bend-limited catheter fromthe target region.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a an example of pattern (e.g., a keystone pattern) ofinterlocking and alternating teeth extending helically around thetubular body, wherein the interlocking teeth each comprise a head regionthat is wider than a base region, arranged so that the head regionsalternate with base regions radially around the tubular body. The valuesprovided for the dimensions (e.g., lengths, widths, angles, etc.) shownin this figure, and all of the following figures, unless specificallyindicated otherwise, are examples only, and may be +/−1%, 2%, 5%, 10%,15%, 20%, 25%, 30%, 50%, 75%, 100%, etc.

FIG. 2A in an enlarged view of a keystone-shaped pattern similar to thatshown in FIG. 1.

FIG. 2B is an enlarged view of another example of a keystone-shapedpattern similar to that shown in FIG. 1.

FIG. 3 is an enlarged view of a keystone-shaped pattern similar to thatshown in FIG. 1.

FIG. 4A is an example of one variation of a portion of a bend-limitedcatheter device as described herein, shown compressed along its length.

FIG. 4B shows the portion of the bend-limited catheter device of FIG. 4Aexpand from a compressed elongate length.

FIG. 4C shows the portion of the catheter device of FIG. 4A and 4B bentto a locking angle.

FIG. 5A is another example of a pattern (e.g., a T-shaped pattern) ofinterlocking and alternating teeth extending helically around thetubular body.

FIG. 5B is an enlarged view of a portion of the pattern of FIG. 5A.

FIG. 6A shows an example of a bend-limited catheter device that bendsfreely out of the long axis of the catheter device until reaching alocking radius (at the locking bend angle), beyond which bending isprohibited.

FIG. 6B is an example of portion of a tubular body of a bend-limitedcatheter, showing a cut-out kerf forming a pattern of interlocking andalternating teeth extending around the tubular body of the catheter.

FIG. 6C is an example of a lateral stiffness profile for a series ofexemplary bend-limited catheters showing the lateral stiffness along thelength for the catheters. The distal ends of the catheters have a verylow stiffness for bend radiuses greater than the locking bend radius(e.g., while bending at angles greater than then the locking bendangle), as shown.

FIG. 7A is a table illustrating different features and variables(including ranges) that may be incorporated into any of the apparatusesand methods described herein.

FIG. 7B is a table illustrating different features and variables thatmay be incorporated into any of the apparatuses and methods describedherein.

FIG. 8A is a graph showing an exemplary profile for cantilever bendstiffness for a catheter apparatus as described herein.

FIG. 8B illustrates one example of cantilever bend stiffness.

FIG. 9A is a graph showing an exemplary profile for Euler buckling for acatheter apparatus as described herein.

FIG. 9B illustrates one example of Euler buckling.

FIG. 10A is a graph showing an exemplary profile for torsion resistancefor a catheter apparatus as described herein.

FIG. 10B illustrates one example of torsion resistance.

FIG. 11A-11D illustrate examples of positioning and/or operatingcatheters within a vasculature model (e.g., cardiac vasculature). FIG.11A shows an example of a catheter such as those described herein overthe aortic arch, not able to make the bend into the (model of the)Brachial artery. FIG. 11B illustrates the brachial artery deforming toallow the catheter to make turn/bend. FIG. 11C illustrates an example ofa catheter configured to make the turn into the Brachial artery andresist prolapse. FIG. 11D illustrates an example of a catheter apparatusconfigured without sufficient bend liming (e.g., with a maximum bendangle greater than a threshold) showing the catheter apparatus makingthe turn into the Brachial artery, but the bend limiting does not resistprolapse into the ascending aorta.

FIG. 12 illustrates one example of a pathway through the vasculature forPE treatment.

FIG. 13 illustrates one example of a catheter as described hereinresisting prolapse into the descending aorta.

FIGS. 14A and 14B illustrate locking one example a catheter apparatus asdescribed herein within a straight section of a vessel. FIG. 14A showsthe apparatus in the vessel prior to locking; FIG. 14B shows an exampleof the same catheter apparatus after locking (by advancing distallywithout any guidewire or other support element within the catheter),driving against the internal lumen of the vessel.

FIGS. 15A and 15B illustrate locking one example a catheter apparatus asdescribed herein within a curved section of a vessel. FIG. 15A shows theapparatus in the vessel prior to locking (able to flexibly move withinthe vessel, including any turns/bends). FIG. 15B shows an example of thesame catheter apparatus after locking (by advancing distally without anyguidewire or other support element within the catheter), driving againstthe internal lumen of the vessel.

FIG. 16 illustrates one example of straightening of a catheter asdescribed herein.

FIGS. 17A-17B illustrate one example of bending/curving a catheter asdescribed herein.

FIG. 18 illustrates one example of a catheter apparatus as describedherein having two zones.

FIG. 19 is a graph illustrating anchor force in a vessel comparing acatheter apparatus as described herein with a prior art catheter.

FIGS. 20A-20B illustrate kickback that may occur in operation of a priorart catheter when compressing the prior art catheter.

FIGS. 21A-21B illustrate catheter apparatus as described hereinresisting kickback and/or buckling.

FIGS. 22A-22C illustrate one example of a catheter apparatus that isconfigured to lock by telescoping over a distal tip gasket.

FIG. 23 is an example of a catheter apparatus configured to lock havinga forward-facing element to prevent or inhibit backward movement of theinner member relative to the outer member.

FIG. 24 is an example of a catheter apparatus configured to lock havingan inflatable element to prevent or inhibit backward movement of theinner member relative to the outer member.

FIG. 25A is an example of a catheter apparatus as described hereinincluding at least one pull wire (shown untensioned); FIG. 25B shows theapparatus of FIG. 25A with the pull wire in tension.

FIG. 26 is a graph illustrating how the ease of tracking the catheterapparatuses described herein can be affected by the state (compressed,relaxed, extended) of the apparatus, as compared to the flexibility ofany lamination on the catheter apparatus.

FIG. 27 is a graph illustrating how bend limiting can be affected by thestate of the catheter apparatus (e.g., compressed, relaxed, extended) ina laminated catheter.

FIG. 28 illustrates how compression resistance of the catheter apparatuscan be affected by the state (e.g., compressed, relaxed, extended)during in a laminated catheter.

FIG. 29A schematically illustrates operation of one example of acatheter apparatus with multiple balloons, not inflated. These balloonsmay passively follow the geometry of catheter.

FIG. 29B shows the catheter apparatus of FIG. 29A with the balloonsinflated. The longer balloon on the left encourages the catheter tostraighten, while the shorter balloon on the right encourages bending.

FIG. 30 shows another example of a catheter apparatus as describedherein, including a cut-away region.

FIG. 31 shows an enlarged view of the catheter apparatus of FIG. 30.

FIG. 32 is an example of a section through the exemplary catheterapparatus of FIG. 30, in a slightly enlarged view.

FIG. 33A schematically illustrates an example of a bend-limited catheterdevice having a plurality of different regions with different benddiameters (and therefore locking bend angles).

FIG. 33B is a schematic example of a bend-limited catheter device havinga non-spiral design or pattern of interlocking keystone teeth radiallywrapping around the perimeter of the catheter with a variable (shown asdecreasing) density of interlocking keystone teeth along the distal toproximal length of the catheter.

FIG. 33C is a schematic example of a bend-limited catheter device havinga spiral, e.g., helical, pattern of interlocking keystone teeth radiallywrapping around the perimeter of the catheter with a variable (alsoshown as decreasing) density of interlocking keystone teeth along thedistal to proximal length of the catheter.

FIG. 34A shows an example of a non-uniformly bend-limited catheter thatis configured to have different locking radiuses in different directionsout of the long axis of the catheter, beyond which the tubular body doesnot allow further bending. The catheter may bend freely (e.g., withlittle if any force required to bend the catheter) until the catheter isbent to a curve having a bend radius that exceeds the locking radius(e.g., then the bend angle is greater than or equal to the locking bendangle); in FIG. 34A the locking radius (and therefore the locking bendangle) is greater in the north direction than any other direction out ofthe long axis of the catheter.

FIG. 34B is an example of a keystone-shaped pattern (showing the top ornorth side of the catheter) that is non-uniform around the perimeter ofthe catheter, arranged so that each tooth of the interlocking andalternating teeth shown forms a tooth angle between a line extendingthrough a width of the head region (e.g., the flattened top of thekeystone-shaped tooth) and a line extending from the head region and thebase region (the angled-in wall(s) of the keystone-shaped tooth), andthe tooth angles of the interlocking and alternating teeth vary radiallyaround the tubular body so that the locking radius of the potion of thelength of the tubular body varies radially around the tubular body.

FIG. 35A is an example of a bend-limited catheter device having multipleregions of one or more cut-out kerfs forming a pattern of interlockingand alternating teeth extending around the tubular body; in thisexample, one of the regions (“zone 2”) is configured to have a greaterlocking radius (and therefore the locking bend angle) in one direction.

FIG. 35B shows curve profiles of the exemplary bend-limited catheter ofFIG. 35A illustrating the different bend locking radiuses for thedifferent regions in different directions or orientations.

FIG. 35C is an example of portions of a bend-limited catheter devicesuch as that shown in FIG. 35A, showing different regions along theelongate body of the catheter; the first region is configured to havedifferent locking radiuses around the perimeter of the catheter (e.g.,by modifying the tooth angles of the keystone-shaped teeth), and thesecond region is configured to have a uniform locking radius around theperimeter.

FIG. 36 is an example of a portion of a non-uniformly bend-limitedcatheter device having different locking radiuses around the perimeterof the catheter (e.g., by modifying the shape and/or size of thekeystone-shaped teeth.

FIG. 37 is an example of a non-uniformly bend-limited catheter device inwhich the pitch between longitudinally-adjacent teeth changes over thelength of the catheter device, similar to that shown in FIGS. 33A-33C.

DETAILED DESCRIPTION

Described herein are bend-limited catheters (e.g., apparatuses,including devices and systems) and methods of using them. A bend-limitedcatheter as described herein is typically freely bendable at anglesgreater than the locking bend angle, e.g., when the bend radius is lessthan the locking bend radius; the device will typically limit or preventbending beyond the locking bend angle. Thus, the device may beconfigured to bend freely in a direction out of a long axis of thecatheter device without requiring a substantial amount of force, such asby applying less than a few grams of force when bending below thelocking bend angle. For example, the lateral stiffness of the catheter(or of a bendable but bend-limited region of the catheter) may be lessthan Z grams (e.g., where Z is 150 g, 125 g, 100 g, 75 g, 50 g, etc.)when the bend angle of the region is below the bend locking angle. Thismay also be described as when the bend radius is greater than thelocking bend radius. When freely bending, the unsupported catheter maybe floppy or loose. It is generally not possible to bend the same regionof the catheter more tightly than the locking bend angle (e.g., to havea bend radius less than the locking bend radius).

In general, the bend-limited catheters described herein may include oneor more bend-limited regions along their length, which may havedifferent configurations in order to have different locking bendradiuses and locking bend angles, as compared to other bend-limitedregions along the length and/or as compared to other regions of the samebend-limited region around the perimeter of the catheter.

The bend-limited catheters described herein are typically formed of atube of rigid material, such as a metal or polymeric material (e.g.,stainless steel, tungsten, Nitinol, etc.) that may be cut to form thebend-limited region(s). Thus, the tube of rigid material may include oneor more cut-out kerfs forming a pattern of interlocking and alternatingteeth extending around the tubular body. Each tooth of the interlockingand alternating teeth may comprises a head region (which may be flat orflattened) that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body.The pattern, including the width of the kerf, the shape and dimensionsof the teeth and the spacing (the pitch and/or backbone region) may beconfigured to so that the bend-limited region is freely bendable whenbent out of the long axis of the catheter (e.g., angles from 180degrees/unbent down to the bend locking angle.

Any of these catheter devices may include a sealing material, e.g., amaterial having a low durometer, such as a polymeric material (e.g.,silicones, elastomers, rubbers, urethanes, etc.) extending across and/orinto the cut-out kerf that may prevent fluid from passing out of thelumen of the catheter. The material properties and/or the thicknesses ofthe sealing material may be selected so that the material (which may bea sheath, coating, etc.) does not add significant resistance to bending,particularly when the device is bent at angles greater than the lockingbend angle.

The apparatuses, including in particular the bend-limited catheters,described herein may be used as part of any surgical procedure, such asminimally invasive (MI) vascular procedures. A catheter is a generally atubular medical device that is inserted into a body cavity, duct, space,or vessel. MI catheter procedures are performed millions of times a yearin the US. Bend-limited catheter may provide necessary properties whenperforming MI vascular procedures. Such bend-limited catheters may havea low column stiffness initially (e.g., they may bend or buckle whenpushed until the locking ben angle is reached), but may be torqueable.For example, these catheters may be configured to rotate when twistedfrom the access point to the tip of the catheter, even over very longlengths, e.g., 0.5 to 1.5 meters. Further, these devices may be ofextremely low profile, so that the device have a very thin wallthickness, providing a maximum inner diameter (ID) for MI procedureswith a minimum outer diameter (e.g., a 0.001″ to 0.025″ thick wall). Thebend-limited catheter devices described herein may typically include abend radius that is limited or locked to reduce or prevent excursions,kinking, etc. Thus, these devices may function as a limitingendo-skeleton that creates a high-confidence, highly predictable shapewhen used in vascular procedure. Typically, these devices may form alocking shape shaft, so that the distal to medial shaft shape is locking(e.g., curved or straight shape locking, resulting in an increased bendstiffness at a locking bend angle). In any of these apparatuses, thelocked form of the device may provide a uni-directional friction. Thedevice may bend and lock within the vessel, so that the catheter ODengages the wall of the lumen as the device bends within the vessel; theintermediate or final catheter shaft configuration (bends) may engagewith the vessel wall(s) in order to improve positioning of the cathetertip and prevent movement of the distal end of the catheter during use.

A bend-limited catheter (e.g., bend-limited support catheter) asdescribed herein may optionally include a distal tip anchor. Thecatheter itself may be formed of a metallic frame (e.g., endoskeleton)that includes the cut-out kerf region forming the plurality ofinterlocking teeth. The catheter may also include a sealing material in,on, or over the kerf cut-out region. For example an inner and/or outerlamination, or skin, may be included.

In some variations, the bend-limited catheters described herein mayinclude five or more components; unlike other catheters, the middlereinforcement (typically a braid or coil element) is replaced amechanospinal element (“endoskeleton” or ES) formed of a rigid, and insome variations metallic, tube which works in unison with a tensionelement and distal friction element to create the properties discussedabove. Thus, the tubular body is typically a rigid tubular body and maybe referred to as an endoskeleton, or ES herein.

The catheters described herein may anchor the distal end of the catheterat or near a target site within the lumen of a vessel. Fixation/lockingof catheter tip location relative to the access location may allow thecatheter to be used to support loads, including compression loads duringoperation of one or more devices through the lumen of the deployedcatheter without substantially displacing the catheter tip. Typically,access to vascular procedures/indications (e.g., neuro, peripheral,structural heart) are done through femoral arterial or femoral venousvessels. Vascular indications require small bore long length catheters(0.021″ to 1.5″ OD range by 1.5 meters long). Peripheral vascular MIprocedure typically use larger shorter catheters (e.g., 0.065″ to 0.183″OD). Structural heart leverages medium length catheters (e.g., 65-90cm), femoral artery to heart (e.g., 0.065″ to 0.23″ OD). Thebend-limited catheters described herein may be used for any of theseindications.

In order to stabilize (e.g., fix or anchor) the catheter distal tip at atarget location, bend-limited catheters described herein may lock thecatheter tip relative to its target position. The catheter tip willresist forward or backward motion (kickback). The bend-limited catheterwill therefore anchor within the conduit (blood vessel, bile duct,urinary, bowel, fallopian tubes, etc.).

The mechanospinal, column support portion of the device may be made froma metallic element laser cut to create a skeletal structure having acut-out kerf region that is formed in to a plurality of interlockingteeth. The skeletal structure including these teeth may have featuresthat allow for precise control of column stiffness, torque transfer,bend radius limitation, and shape locking. When the bend-limitedcatheter, and particularly the region including the pattern ofinterlocking teeth, is loaded (compression, tension, bending), it mayrespond by either straightening or become curved. A catheter thatstraightens or curves when loaded will then engage the conduit (tube)that it is located within (e.g., within the vessel). The size of theconduit and the amount of curvature of the conduit relative to theinventive catheter may affect the catheter's wall engagement, such asthe tendency to anchor/resist motion. Larger conduits may benefit fromgreater catheter straightening or curving.

The catheters described herein may be used in any natural human or otheranimal conduit, such as a blood vessel, bile duct, urinary, bowel,fallopian tubes, etc.

In some variations, the catheters described herein are configured foruse as one or more of: a guide catheter (e.g., 0.088″ or largerdiameter); a PE catheter (e.g., having about 0.031″ (10F) inner); anintermediate catheter (e.g., 0.071″ ID); a structural heart catheter(e.g., having a 0.209″ (16F) size), etc.

The bend-limited structures (e.g., teeth) can be created by cuttingpatterns into rigid tubing. The resulting teeth structures may allow thetube to bend. Features of the kerf and/or teeth may engage to limit orreduce the amount of bending.

FIG. 1 shows an example of a pattern for, e.g., a laser cutting pathinto a round tube, to form one or more cut-out kerfs forming a patternof interlocking and alternating teeth extending around the tubular body.For this example, the 0.3294 dimension is the perimeter of the tube, ifcut open and flattened. The B-direction is the long axis of the tube.The pattern angle 103 is the angle relative to an axis orthogonal to thelong axis. When this pattern is cut into a tube, the cut-out teeth mayallow the tube to bend freely, at least to a locking radius (lockingangle). In this example the teeth correspond to Keystone-shaped features(teeth) 103 that may limit the amount of bending to the locking angle(or locking radius). During bending, the aspect of the tube that is onthe inside of an arc may or may not compress. Meanwhile, the aspect ofthe tube that is on the outside of the arc will be longer relative tothe inside of the arc. This longer feature is created by movement of theteeth relative to each other. Also, these teeth limit the amount ofbending, as described below.

FIGS. 2A and 2B illustrate examples of laser-cut tubes having slightlydifferent keystone-shaped patterns. In FIG. 2A, a region similar toregion “B” of FIG. 1, is shown, illustrating an example of a patternincluding a keystone shape (which is shown as a truncated isoscelestriangle, missing the top apex) that has a tooth angle 221 (e.g., theangle between the flat region of the head region and side wall formingthe base) that is about 78 degrees, while in FIG. 2B the tooth angle221′ is shown as 58 degrees. In any of the drawings, including theengineering drawings described herein, the dimensions (lengths, widths,angles, etc.) are for illustration only; actual dimensions may be variedby +/−5%,10%, 15%, 20%, 25%, 30%, etc. of the value(s) shown).

FIGS. 2A and 2B also illustrate the spacing between the adjacent rows ofa teeth, including the pitch 215, from the start of first row of teethto the start of a second row of teeth, and the backbone 219 (the spacebetween the end of the first row of teeth and the start of the next rowof teeth along the length). The keystone shape, and particularly thekerf width 217, 217′, height of the tooth 220, and the tooth angle 221,may be selected to set the locking bend angle (e.g., locking bend angleper unit of length, as described below) and/or the bend radius. FIG. 3shows another example of an enlarged view of a cut-out kerf regionforming a pattern of interlocking and alternating teeth 303 extendingaround the tubular body. The tooth angle 321 is shown in the enlargedfigure (in this example is 78 degrees), as well as the expansion area323 (sowing the possible expansion of the length of the catheter bymoving between points A and B for this particular circumferential regionof the pattern). The pitch of the teeth in this example includes theheight 320 of the tooth as well as the backbone 319 (and in thisexample, the kerf width 317). In FIGS. 3 (as well as the examples shownin FIGS. 2A-2B) the keystone-shaped teeth 403 include a flatten headregion 330, a narrow-diameter base region 332, and a pair of sides 333,333′.

FIGS. 4A-4C shows another example of a laser-cut tube 401 forming abend-limited catheter device 400. In FIG. 4A, the device is shownresting, un-extended state, which is compressed in the axial direction420. As described above, the keystone-shaped teeth 403 include a flattenhead region, a narrow-diameter base region, and a pair of sides; thesides of each tooth engage and limit extension when pulled in theproximal-to distal direction, as shown in FIG. 4B. FIG. 4B shows thelaser-cut tube 401 of FIG. 4A, showing the catheter in expansion 422,with the ends being pulled apart so that the pattern of interlocking andalternating teeth 403 extending around the tubular body separate. InFIG. 4B, the catheter 400 is expanded by the expansion area of eachtransverse ring (or spiral) of teeth in the pattern. Generally, for thecatheters described herein, the expansion area is greater than the kerfdiameter by greater than about 1.15×, 1.2×, 1.25×1.5×, 1.75×, 2×, 2.25×,2.5×, 2.75×, 3×, 3.5×, etc. (e.g., between about 1.2× and 6×, betweenabout 1.2× and 5.75×, between about 1.2× and 5.5×, between about 1.2×and 5.25×, between about 1.2× and 5×, between about 1.2× and 4.5×,between about 1.25× and 4.25×, between about 1.25× and 4×, between about1.25× and 3.75×, between about 1.2 and 3.5×, etc.).

In FIG. 4C the catheter 400 is shown bending, showing the compression ofadjacent keystone-shaped teeth on the inner side 455 and the expansionof keystone shapes on the outer side 457. The gaps between the keystonefeatures close on the inside of the arc 455 while the gaps increasealong the outside of the arc 457. The keystone-shaped teeth engage andlimit bending along the outside of the arc. In FIGS. 4A-4C, the laserkerf is 0.001″. The tooth height is 0.013″ in this example. In thisexample, the tooth angle is somewhat high (e.g., 72-80 degrees), and thenumber of teeth per circumference of the tube is relatively low (e.g.,12), resulting in a surface that is less smooth than variations having alarger number of teeth/circumference.

Although the keystone-shaped teeth shown in FIGS. 1-4C may be preferred,other shapes, including more rounded keystone shapes, teardrop-shapes(and particularly teardrop shapes having a flattened head region), othersuch shapes may be used, including asymmetric shapes (e.g., shapes inwhich the tooth has multiple tooth angles, such as a first side having atooth angle that is different from the tooth angle of the other side).For tooth shapes in which the sides are not flat or substantiallystraight between the head region and the base region of the tooth (e.g.,in a teardrop or flatten-head teardrop shape, T-shapes, etc.) the toothangle may be the angle of an average, mead, or median line through theside, connecting the base region to the head region.

FIGS. 5A-5B illustrate an example of a T-shaped tooth 501. In thisexample, the bend angle 521 is 90 degrees, as the sides 533 areperpendicular to the diameter of the head region 530 and the base region532. The expansion area 517 shows the movement of the interlocking teeth501. The expansion area 523 is approximately the same distance as thekerf diameter 519; the T-shaped tooth element is restricted from movingany further in the long axis than the kerf diameter. Thus, the expansionarea is limited to the cut-out kerf diameter in this example. The pitch515 show is the distance from one set of teeth to the next, along thelong axis of the tube.

FIG. 6A illustrates an example of a bend-limited catheter 601 configure(at its distal end region) to bent to a full locking bend angle (β) perunit length. The locking bend angle 609 may be expressed as a lockingbend angle per unit of length, also referred to herein as the minimumbend angle, wherein the length 605 is the midline 603 through thebending catheter. In some cases it may be convenient to refer to thebend angle relative to the long axis or out of the long axis of thecatheter; in FIG. 6, the locking bend angle relative to the long axis611 (or equivalently, the bend angle relative out of the long axis ofthe catheter) is shown as α, 610, and is 90-β (e.g., 90 minus thelocking bend angle 609). The bend radius (r_(bend)) 607 corresponding tothis minimum bend angle, for a tube having a tube diameter 613, isshown. Generally, the bend diameter (d_(bend)) is twice the bend radius.The bend angle and bend radius for a particular region (e.g., at a pointon the length of the catheter) may be measured as from a planetransversely through the catheter at that particular region (e.g.,between a first point 619 and a second point 621 at the boundaries ofthe particular region) and a second plane transversely though thecatheter at a second spot.

FIG. 6B illustrates a side view of one example of a portion of abend-limited catheter having a pattern of interlocking and alternatingteeth (shown as keystone-shaped teeth) extending around the tubularbody. In the portion of the pattern shown, a single cut-out kerf formsall of the interlocking and adjacent keystone-shaped teeth, whichspirals helically around the tubular body. Alternatively oradditionally, the pattern may form multiple separate rings (e.g., eachformed by a separate cut-out kerf) that re arranged adjacent to eachother (e.g., shown in FIG. 33B). The pitch 831 of teeth between the rowsof teeth (in this helically-arranged example) is shown as the distance(along the long axis or length of the tube) of the tooth and thebackbone region 819, which may also include the kerf diameter, as shown.The helix angle 833 between the rows are also shown.

The bend-limited catheters descried herein may be configured so thatthey are freely bendable from an unbent/straight configuration withoutthe application of a substantial amount of force (e.g., less than 150 g,less than 125 g less than 100 g, less than 75 g, less than 50 g, etc.)to bend until reaching the locking angle. Once bent to the lockingangle, the catheter may not bend further without deforming. This may bereflected in the stiffness of the catheter, so for bending at anglesbefore reaching the locking angle the stiffness is very low over theportion of the catheter including the pattern of interlocking teeth asdescribed above, e.g., at the distal and/or proximal regions of thecatheter; more distal regions may be made stiffer (e.g., by adjustingthe pattern of interlocking teeth, and/or by adding stiffing layers orelements. FIG. 6C illustrates an example of a lateral stiffness profilefor a set of exemplary catheters 651, 653, 655, 657 having distal, andin some cases proximal, regions of increasing relative length that areconfigured as a bend-limited regions. The different lines shownrepresent different catheters having freely bending distal (or distaland proximal) regions of different lengths. The lateral stiffnessesshown in FIG. 6C were all estimated for the bend-limited regions atangles (relative to the long axis of the catheter) that are below thelocking bend angle (e.g., at bend radiuses greater than the locking bendradius as described in FIG. 6A), so that catheter was extremely flexiblein this range. Note that the different catheters illustrated may havedifferent locking bend radiuses/different locking angles, or the samelocking bending radiuses/locking angles. The stiffness may be estimatedby applying force between two supports supporting a portion of thecatheter to determine the force required to deflect the portion of thecatheter between the supports.

A number of different variables (features) may affect performance of thedevices as described herein. For example, FIGS. 7A and 7B are tablesillustrating some of these. Generally, numerous variables influence themechanical characteristics of the catheters described herein, includingthe patterned regions. FIGS. 7A-7B identify many of these variables, andprovide some insight in how they may affect the properties of thecatheter. As discussed above, these bend-limited catheter may includeone or more different bend-limiting regions having a lock out anglealong the length of the catheter. The bend limiting regions may becovered by an outer skin lamination (e.g., sleeve, seal, skin, cover,sheath, or the like) that may be applied on an outer, inner or bothouter and inner surfaces. This lamination may create additional supportwhile also creating spring back to original shape. As mentioned above,the cover may be particular thin, though it may have a higher durometer(e.g., durometer of greater than 75 Shore A, e.g., between about80-100). Lamination may influence the bending shapes, bias, and limits.Some of these variables are described in FIGS. 7A-7B. Some of thesevariables are further described in the empirically measured graphs ofFIGS. 8A-10B.

For example, the catheters described herein may be made of stiff(“stiffer”) materials such as tungsten, steel (stainless steel), orother metals, including shape memory metals (Nitinol) and/or rigidpolymers. The shape of the teeth (e.g., tooth angles) may be adjusted toadjust the locking angle (locking radius/locking diameter) and theexpansion area per unit length. Typically larger expansion areas (e.g.,at larger tooth angles, such as between 60-87 degrees) may result in adecrease in the minimum bend radius, providing an increase in the amountof bending, while lower expansion areas (e.g., at smaller tooth angles,such as between 30 and 60 degrees) may have larger minimum bendradiuses, and may decrease the amount of bending. Generally, the toothangle may be between 1 degree and 85 degrees, e.g., between 30 degrees(so that the expansion area is greater than, e.g., 1.2×, the cut-outkerf diameter) and 87 degrees, between 35 degrees and 85 degrees,between 40 degrees and 85 degrees, between 45 degrees and 85 degrees,etc. As will be described below, in some variations the same cathetermay include regions of different patterns of interlocking teeth havingdifferent properties allowing for different bending and locking angles(see, e.g., FIG. 33A, described below). The pitch may be between 0.005and 0.3 inches; more generally, the ratio of the pitch per diameter ofthe tubular body (e.g., outer diameter, inner diameter or averagediameter) may be between about between 0.03 and 0.90 (e.g., some regionsmay be between 0.03 and 0.3, or between 0.05 and 0.3, or between 0.09and 0.3, or between 0.3 and 1, or between 0.3 and 0.95, or between 0.3and 0.9, etc.). The total number of tooth per circumference (tooth perrevolution) may be between 3 and 65, e.g., between 3 and 60, between 6and 60, between 8 and 60, between 12 and 60, between 18 and 60, between20 and 60, between 22 and 60, 12 or more, 14 or more 16 or more, 18 ormore, 20 or more, 22 or more, etc.). The axial width of the backboneregion may be between 0.002 and 0.060 inches, or may be expressed as apercent of the pitch (e.g., 60% or less, 50% or less, 40% or less, 30%or less, 25% or less, 20% or less, etc.); the lower the percent of thepitch taken by the backbone, the more teeth may be packed or the tallerthe teeth may be used (allowing for larger tooth angles), which mayincrease flexibility and/or bend angle. Other factors may include thepattern angle (e.g., the angle of the line of teeth formed by thecut-out kerf relative to the long axis of the catheter), which may bebetween, e.g., 1-40 degrees, and the tooth shape.

The catheters described herein are typically thin walled, but may have arelatively larger inner diameter (e.g., between 0.010 inches and 1.5inches) when the outer diameter is approximately 0.001 inches thick(e.g., between 0.0005 and 0.005 inches).

FIGS. 8A-10B illustrate various examples of physical properties of someof the variations of the bend-limited catheters described herein. Forexample, a bend-limited catheters may have a cantilever bendingstiffness, showing an inflection point define by the increase in bendingstiffness. The bend limited catheter has locked out and bendingstiffness increases significantly, as shown in FIGS. 8A-8B. FIGS. 9A-9Band 10A-10B illustrate the invention Euler buckling and TorsionResistance characteristics, respectively. The catheters described hereininclude a balance of flexibility to make turns and gain access, whileproviding limiting bending under compression and bends.

In use, the bend-limited catheters described herein may be helpful in avariety of therapeutic indications, including non-invasive andminimally-invasive surgical interventions, as they may be used in thebody, including in highly tortious anatomy such as the neruovasculature,with high tracking over a guidewire, given their very low stiffness whenbending out of the long axis of the catheter before reaching the lockingangle (e.g., may be relatively loose and floppy) but may lock whenbending out of the long axis to the locking angle, and may have a veryhigh load capacity at the locking angle without breaking, deforming orbucking. Further, and surprisingly, driving these catheters from theproximal end (e.g., outside of the patient) may cause the catheter tolock up within the patient vessels without substantially displacing thedistal end of the catheter, preventing or limiting “back out” of thecatheter from the target region. For example, FIGS. 11A-11D illustratethe comparison of a bend-limited catheter within a tortious model of apatient's vessel, including an aortic arch and brachial cephalic artery.In the examples shown in FIGS. 11A and 11D the catheter used is stifferthan the bend-limited catheters shown in FIGS. 11B and 11C, and cannotaccess the target vessels. In FIG. 11A, the target pathway 1105 is shownby the guidewire. The catheter 1107 is not able to make the bend in theaortic arch region to track up to this target path. FIGS. 11B and 11Cshow how a bend-limited catheter having the right balance of flexibilityand locking angle may access and provide resistance to prolapse in atight and tortious region such as the ascending aorta and aortic valve.In FIG. 11B, the bend-limited catheter 1109 (an example havingkeystone-shaped teeth) tracks over the guidewire in the target path1105, as shown. In FIG. 11C the guidewire has been removed, and a loadhas been applied (manually, shown by holding the distal end fixed andadvancing the proximal end of the catheter, resulting in a force 1119that would otherwise prolapse the catheter). Rather than prolapse intothe aortic arch 1113, the catheter locks at the locking angle 1115shown. FIG. 11D illustrates prolapse 1122 with a catheter 1125 that doesnot lock at a locking angle within the aortic arch.

The bend-limited catheter described herein, including those havingkeystone-shaped teeth, can be tuned for use in other vessels ofconduits. For instance, to reach the pulmonary artery for pulmonaryembolism treatment, a catheter must be able to gain access through thevenous system, through the right side of the heart. FIG. 12 shows theaccess path to the pulmonary artery form the right femoral vein. Arrowsillustrate regions 1205, 1207 where a bend-limited catheter may includea locking angle to resist prolapse. FIG. 13 illustrates an example of abend-limited catheter 1301 that include a locking angle sufficient toresist prolapse into the descending aorta 1309.

The bend-limited catheters in various indication will provide superiorcatheter support, either as a guide or stand-alone self-support due tothe inventions ability to gain access, follow vessel curvature withessentially infinite column stiffness, and provide essentially infinitetorque-ability. The bend limited catheters described herein maytherefore resist kinking, coiling and prolapse. Further, these devicesmay lock under load compressive load (e.g., bending stiffness increasewhen compressed) or by a proximal end laid out feature.

In any of the bend-limited catheters described herein the catheter mayhave two or more locking (bend limiting) zones or regions. In somevariations, the catheter may include one or more puller threads to applycompressive force to lock the catheter. For example, the catheter mayinclude two puller threads, as shown in FIGS. 14A-14B. FIGS. 14A-14Billustrate locking/anchoring invention in a straight section of aconduit.

The bend-limited catheters described herein are also configured to lockagainst the walls of the vessel when a compressive force is applied;this locking may help anchor the devices within the vessel, and may helpprevent or reduce pull back of the distal end of the device from thetarget region. For example, FIGS. 15A-15B illustrate locking/anchoringof a bend-limited catheter in a curved conduit (e.g., vessel, bodylumen, etc.). In some variations, tip anchoring may be achieved byhaving a small bore pulling element attached to the catheter distal tipoff its central axis. This may be called an actively actuated tipanchor. A puller wire may be placed in tension, the tip then curvesuntil it bumps into a vessel wall of the bend limited element locks out.Alternatively the device may be locked by advancing proximally.

FIG. 16 illustrates puller along central axis. In some variations thebend-limited catheter may be biased to tend to straighten into thisconfiguration. FIGS. 17A-17B illustrate the use of a puller 1705 that isoffset from central axis to bend and/or lock a bend-limited catheter1701. FIG. 18 illustrates a catheter 1801 having two zones withdifferent regions of actuation (bend-limited regions, formed by two ormore patterns of alternating teeth, as described above). These zones canalso have different curving (or straightening) capabilities and may be(in this example) actuated by two different pull wires 1805, 1805′.Anchoring force may be measures, such as in the example shown in FIG.19. A bend-limited catheter 1901 was compared to typical (commerciallyavailable) guide MI catheter 1905, and found to have substantially lowertip movement per compressive force. The catheters were placed in ananatomical vessel model as shown in FIGS. 20A-20B. Catheters wereintroduced 2001 and the location of the catheter tip was placed near atarget site 2002; the catheter was placed over a guidewire or guidecatheter to provide the rigidity necessary or initial placement. Once inposition, the guidewire and/or guide catheter may be removed. Acompression force 2007 at the tip was applied to both catheters. Theforce needed to move the tip backwards (kick back) was measured. Higherforce is preferred (translates to more tip stability and more accuratetip location. This catheters described herein, leveraging both bendlimit and tip anchor proved superior to tip movement, i.e., the tiprequired more force to move backwards 2005.

FIGS. 20A-20B shows the setup using a traditional catheter. Compressiveaxial load at the distal end causes kickback within the length of thecatheter, resulting in distal tip backwards movement. FIGS. 21A-21Bshows a bend-limited catheter as described herein having anchoring andbend-limiting features. Anchoring and bend resistance (e.g., prolapseresistance, anti-excursion) reduces or eliminates backwards movement ofthe distal tip, as shown. The locking feature (e.g., locking angle) ofthe bend-limited catheter described herein creates a stable, non-movingtip position within the vessel. Once the tip is anchored, a secondcatheter can be inserted, using, for example, telescopic catheters.Thus, a first bend-limited catheter may act as a guide catheter. Asecondary or inner catheter may also be a bend-limited catheter.

Due to the diameter ratios of the smaller catheter within thebend-limited outer catheter (large ID/OD), the locking may be lesseffective. However the bend-limited catheters described herein maytransmit the outer bend-limited catheter's locking/anchoring to theinner bend-limited catheter's surface. This may form a telescopingcatheter system, as shown in FIGS. 22A-22C. The inner (small diameter)bend-limited catheter may be actively locked to the outer bend-limitedcatheter, which may then produces a stable platform for use withadditional components (e.g., surgical tools). This is illustrated inFIGS. 22A-22C, showing the locking nature of outer bend-limited catheterrelative to the inner bend-limited catheter as a passive lock (activatedby a property of the bend-limited catheter rather than requiring activeengagement by a user). The outer (e.g., guide) bend-limited catheter tipmay include a reverse/backward sliding element, e.g., pulling the innerbend-limited catheter backwards relative to the guide. The directionalelement may allow forward motion with minimal force. When the innerbend-limited catheter is pulled backward, the force increases, resistingthe reverse sliding force. The reveres motion of the inner bend-limitedcatheter may be transferred to the outer (larger/stiffer, stronger andlocked/anchored) bend-limited catheter as shown. The force transfer isto a larger outer catheter. The unidirectional tip element in thisinvention is accomplished using any of the examples above. FIGS. 23-24show a locking region in the coaxial bend-limited catheter (e.g., in theinner bend-limited catheter) that may also be used.

FIG. 22A-22C illustrates a thin walled elastic tip taper section (1-10mm long) which has a decreasing diameter (ID/OD match) to 10% smallerthan the ID of a bend-limited catheter. The taping tip creates a nearone-way valve. As the inner co-axial catheter advances forward throughthe outer catheter tip taper section, the taper stretches around theinner catheter, the taper section stretches open and the inner catheteris advanced. When the inner bend-limited catheter is puller (directionreversed), the taper grips the inner catheter and transfers load to theouter bend-limited catheter, which is locked to the vessel wall, eitherstraightening lock or curving lock.

FIG. 23 illustrates a forward-facing filament element that resists innerbend-limited catheter movement backwards, relative to outer bend-limitedcatheter. Similarly, FIG. 24 illustrates an inflating balloonlock/gasket design, where the balloon squeezes the tip of the innerbend-limited catheter. This inhibits backwards movement of the innercatheter relative to the outer bend-limited catheter.

Alternatively or additionally, a stented valve design may be used. Forthis design, a stented valve can be used to reduce or eliminatebackwards movement of the inner catheter relative to the outer catheter.For example, the stent tends to reduce in diameter when the distalaspect of the stent element is pulled towards the proximal end of thestent. This stent-like feature can be positioned at the distal end ofthe outer catheter, similar to previous methods shown in FIGS. 23 and24.

The examples of methods described below illustrate the application ofcompression to a body of a bend-limited catheter to facilitate positionand orientation locking. This may maintain the tip of the bend-limitedcatheter in a target distal position while the vessel is treated. Forexample, in some variations, the method may maintain or advance theproximal end position of the bend-limited catheter to maintain acompressed state of the bend-limited catheter; the b bend-limitedcatheter may be used as a guide catheter (GC), for example. In thismethod, the bend-limited catheter may be advanced through an optionalsheath and to its targeted position by pushing on proximal end ofbend-limited catheter. The bend-limited catheter can be deliveredpreloaded with a supportive inner dilator catheter and/or an optionalguide wire to aid in delivery. Once the bend-limited catheter tip is atthe target location, the dilator and/or guidewire can be optionallyfully or partially removed.

The bend-limited catheter may be either maintain in the insertedposition or advanced from the proximal end of the bend-limited catheterto remove slack and/or to compress the length of the bend-limitedcatheter. An advancing or holding force applied by the user may helpforce the bend-limited catheter to move into a radius-lockedconfiguration and/or shape, as described above. The bend-limitingpattern of the interlocking teeth in the tubular body of thebend-limited catheter may make the bend-limited catheter more supportiveand stiff, allowing delivery of other devices through the bend-limitedcatheter without kicking back and out of the patient.

The proximal end of the bend-limited catheter may be secured relative tothe patient by a variety of methods so the bend-limited catheter doesnot uncoil from its compressed configuration. For example, thebend-limited catheter may be secured to the patient via a securement(e.g., tape, Velcro, suture, etc.), and/or the bend-limited catheter maybe secured to the operating table a securement (e.g., tape, Velcro,suture, etc.). The proximal end of the bend-limited catheter may be heldby hand, or by securing the bend-limited catheter through passive oractive friction lock in sheath already placed in the patients' bloodvessel, body or operating equipment (table, bed, etc.).

Optionally, a tightening, deflecting or compression element connectednear the distal end of the bend-limited catheter may be used, includingthrough a feature in the proximal end of the bend-limited catheter. Thisactuation can additionally stiffen the bend-limited catheter to create asupportive structure/tube for delivery of other devices.

In some variations the bend-limited catheter may be operated by distalend actuation to apply compression to the bend-limited catheter. Forexample, an advance bend-limited catheter may be positioned by pushingon proximal end of bend-limited catheter until the distal tip is attarget location; a stiffening inner and/or outer member may be used,such as a guidewire. The position of the proximal end of thebend-limited catheter may be maintained relative to patient. Atightening, deflecting or compression element connected the distal endof the bend-limited catheter may be actuated through a feature in theproximal end of the bend-limited catheter, which may apply compressionforces between the distal end and proximal end of bend-limited catheter,encouraging the bend-limited catheter into a radius-lockedorientation/shape. The radius-locked orientation of the catheter maymaintain the distal positioning and may create a more supportivestructure/tube for delivery of other devices.

In some variations, a pull wire may be used to apply compression to abend-limited catheter. For example, a bend-limited catheter may beadvanced into position by pushing on a proximal end until the distal tipof the bend-limited catheter is at target location (as before astiffening member may be used). The position of the proximal end of thebend-limited catheter may be maintained relative to the patient or theproximal end may be advanced. Tension may be applied to a pull-wirecoupled to the bend-limited catheter while maintaining the position ofthe proximal end of the bend-limited catheter relative to the patient(e.g., by pushing). The pull wire may be fixed to the distal end (or adistal end region) of the bend-limited catheter, and can be pulled fromoutside the patient (as shown by example in FIG. 25A). Tension on thispull-wire may apply a compression along the length of the bend-limitedcatheter, as shown in FIG. 25B. This compression may improve theradius-locked orientation/shape of the bend-limited catheter. Theradius-locked orientation of the bend-limited catheter may maintain thedistal positioning of the bend-limited catheter, allowing actuation tobe more effective.

The bend-limited catheters described herein may be fabricated in amanner that modifies their properties. For example, the extension stateof the bend-limited catheter during fabrication can affect theproperties of the catheter, including trackability (the ability of thecatheter to get to the target location), bend limiting (the ability ofthe catheter to resist bending and lock out in key areas), andcompression resistance (the ability of the catheter to resistcompression during use). The bend-limited catheters described hereintypically have superior control of bend limiting and compressionresistance as compared to prior art devices, which may increase theability to maintain distal tip position during use.

The bend-limited catheters described herein may be in any of three ormore different states of extension prior to (and during) the addition ofsealing (e.g., lamination) materials to the inner and/or outer surfacesof the bend-limited catheter. For example, the catheter may be in acompressed, relaxed, or extended configuration (or some combination ofthese, or intermediate position between these, including bent/curved).This may affect the final shape set of the bend-limited catheter. Themodulus of the sealing material (e.g., lamination) relative to that ofthe spring-like tubular body may influence the properties of thecatheter.

For example, if the bend-limited catheter is laminated when compressed,the tubular body (including the pattern of interlocking teeth) may actlike a coil spring in compression, being held in position by an elasticin tension. When the bend-limited catheter is laminated in a relaxedstate, the tubular body and the sealing material may act like springs inunloaded states. When the bend-limited catheter is laminated in theextended state, the tubular body may act like a coil spring in tension,being held in position by a rubber tube in compression.

The amount of sealing material that protrudes into the kerf, e.g.,between the laser cut edges, may also influences the properties of thecatheter; this may be reflected in the thickness of the sealingmaterial. Further, a minimal amount of sealing material within the lasercut kerf region may result when the sealing material is applied in thecompressed configuration. A nominal amount of sealing material may bepresent in the kerf when the material is applied in the relaxedconfiguration. This sealing material may increase the ability of thebend-limited catheter to bend, by compressing along the inside arcs ofbends.

When the sealing material is applied in the expanded configuration, amaximal amount of sealing material may be laminated into the kerf. Thissealing material may further increase the ability of the bend-limitedcatheter to bend, by compressing along the inside arcs of bends.

FIGS. 26, 27 and 28 for illustrate example of the effects of applyingsealing material (lamination) in various amounts within the kerf region(e.g., applying when compressed, having little material, when relaxed,having a moderate amount of material, or when expanded, having the mostmaterial). These properties may relate to one another for a particularbend-limited catheter and sealing material combination.

In some variations, a thin-wall braided tube can be positioned outsideof the bend-limited catheter to provide bend limiting resistance. Duringcatheter bending, the braided tube may increase frictional resistanceagainst the bend-limited catheter (e.g., the tubular body), reducing thecatheter's ability to lengthen along the outside aspect of the curve.This may limit bending. Variables that govern relationship include:braid material stiffness, braid material size, number of braid ends,braid angle, braid pattern, braid “wall thickness”, braid inner diameterrelative to the tubular body outer diameter, braid material profile(round, square, etc.). Also, a braid can be designed to have diameter“bumps” or angle changes. This facilitates focusing the bend-limitedcharacteristics to localized regions along the bend-limited catheter.The braid can be loose outside the bend-limited catheter, within thesealing material/coating (e.g., lamination), or sandwiched in-betweenthe sealing coating and the tubular body.

As mentioned above, any of these devices may include a balloon that canbe secured to the bend-limited catheter, e.g., on the outside of thebend-limited catheter. When filled with fluid, it may add stiffness tothe catheter. This can help anchor the distal tip of the catheter in adesired location, and/or help resist bending in other locations. Aballoon can be positioned along the length of the bend-limited catheter,on the inside or outside. This balloon may be positioned outside of thebend-limited catheter, or inside of the bend-limited catheter. Theballoon can be in the shape of a straight tube, an arced tube, astraight line, a helix, etc. This balloon does not have to be run alongthe entire length of the ES, but may extend over a small region of thecatheter, nor does the balloon have to be one continuous shape, but maycontain multiple different shapes. Preferably, the balloon may be atubular balloon. This balloon may be actively inflated/activated anddeflated/inactivated from outside the body. FIGS. 29A-29B illustrate oneexample of tubular balloons 2905, 2909 over a bend-limited catheter2901. The uninflated balloons show in FIG. 29A are shown inflated inFIG. 29B.

FIGS. 30-32 illustrate an alternative variation of a bend-limitedcatheter in which flexible metal conduit is miniaturized and used toform the bend-limited catheter. In this example, flat ribbon is shapedinto rings or a helix, and is formed into a long tube, as shown. Theformed shapes interact with each other to allow and limit tube bending.

Any of the bend-limited catheters described herein may be configured asbend-limited catheter devices having multiple different patterns ofinterlocking and alternating teeth extending around the tubular body,formed by the one or more cut-out kerf. The pattern of interlocking andalternating teeth may repeat from a distal region to a proximal regionof the length of the tubular body. As already described above, eachtooth of the interlocking and alternating teeth may comprise a headregion that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body, sothat the catheter bends in a direction out of a long axis of thecatheter device up to a locking radius, beyond which the tubular bodydoes not allow further bending in the direction. Each tooth of theinterlocking and alternating teeth may form a tooth angle between a lineextending through a width of the head region (e.g. or along theflattened head region) and a line extending from the head region and thebase region (e.g., the sides), as described above.

These devices may include a proximal pattern and a more distal patternthat have different properties, and in particular, have differentaverage tooth angles and/or different ratios of pitch to tubular bodydiameter. For example, the average tooth angle of the distal region maybe greater than the average tooth angle of the more proximal region.

FIG. 33A illustrates one example of a bend-limited catheter devicehaving a distal (e.g., first) region 3305 that having differentproperties than the more proximal 3307 (e.g., second) region. The firstregion is located immediately adjacent to the second region, though theymay be separated by an intervening region. One or more additionalregions 3309 may be arranged proximal and/or distal (or between) thefirst and second regions. In some variations the distal end region 3305may begin at the distal end of the catheter and may extend for up to 30or more (e.g., up to about 20, about 22, about 23, about 24, about 25,about 26, about 27, about 28, about 29, about 30, about 31, about 32,about 33, about 35, etc.) cm. The proximal region may be calibrated tobe in the aortic region for a neurovascular catheter, and may extendfrom the distal region for another 20-35 cm (e.g., about 20 cm, about 21cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm,about 27 cm, about 28 cm, about 29 cm, about 30 cm, etc.).

In FIG. 33A, the catheter is configured so that the distal region has ahigher flexibility and smaller locking angle (e.g., larger locking anglerelative to the long axis of the catheter). This may be achieved byusing a pattern of interlocking and alternating keystone-shaped teethextending around the tubular body for the distal portion 3305 in whichthe pattern of interlocking and alternating keystone-shaped teeth mayextends more than 2 cm along the length of the long axis (e.g., between2 and 30 cm, e.g., between 2-29 cm, between 3-28 cm, between 3-27 cm,between 4-26 cm, between 4-25 cm, between 4-24 cm, between 4-23 cm,etc.) comprises keystone-shaped teeth having a tooth angle that isbetween 61-84 degrees (e.g., about 78 degrees in one example). This isillustrated in the enlarged region 3315 of FIG. 33A. The more proximalportion 3307 of the pattern of interlocking and alternatingkeystone-shaped teeth may extend more than 2 cm along the length of thelong axis (e.g., may extent between 2 and 30 cm, e.g., between 2-29 cm,between 3-28 cm, between 3-27 cm, between 4-26 cm, between 4-25 cm,between 4-24 cm, between 4-23 cm, etc.) may have keystone-shaped teethhaving a tooth angle that is between 30 to 60 degrees (e.g., about 58degrees in one example). This is illustrated in the enlarged region 3317of FIG. 33A. The distal portion of the pattern of interlocking andalternating keystone-shaped teeth may have a pitch to tubular bodydiameter ratio that is between 0.09 and 0.30 and a pitch to tubular bodydiameter ratio of the more proximal portion of the pattern ofinterlocking and alternating keystone-shaped teeth is between 0.30 and0.90.

FIGS. 33B and 33C illustrate other examples of bend-limited cathetersincluding multiple regions along their length (including distal regionand proximal regions) having different locking bend angles, smoothness,and/or flexibility. For example in FIGS. 33A and 33B, the proximalregion has a much smaller pitch/tube diameter compared to the moreproximal region. FIG. 33A shows an example in which the pattern ofinterlocking teeth are formed by multiple cut-out kerfs into multipleparallel, transverse rows; FIGS. 33B shows a single helically woundcut-out kerf forming multiple rows of interlocking teeth.

As mentioned above, any of the devices described herein may benon-uniformly bend-limited catheter devices that may include regions ofdifferent locking radiuses around the perimeter of the bend-limitedregion, as illustrated in FIG. 34A. Such devices may be adjustable byrotating the catheter shaft axially, and may therefore act as an activelock/stabilizer in a vessel. In FIG. 34, the bend-limited catheterincludes a much smaller locking bend angle, β (a much larger lockingbend angle relative to the long axis of the catheter, α, as shown inFIG. 6) in the “north” direction 3405; the east 3307, west 3311 andsouth 3309 directions all have similar locking bend angles, as shown,resulting in the non-uniform bending limiting property of the catheter.This may be achieved by adjusting the pattern of interlocking andalternating teeth, as described herein.

The teeth (e.g., keystone-shaped teeth) may form a gradient around theperimeter create a bend limiting element. The keystone gradient may beengineered to produce different amounts of limiting (bend radius bias)depending on the direction the tube is bent. A catheter made with thegradient bias would be able to bend around tight turns (small bendradius) and by torqueing the proximal catheter end from 0 to less than180 degrees (half a turn) the bend radius limiting element wouldincrease and the catheter would create an adjustable locking zone (moreto less bending), to provide an adjustable locking within a vessel(e.g., wedging to wall or tangent touch points), and/or remove theaccess limiting nature of a fixed single bend limiting keystone. Thelocking angle (and correspondingly, the locking diameter/locking radius)may be tuned or adjusted in a non-uniform manner around the perimeter ofthe catheter. FIGS. 34B shows an example of a portion of a cut-out kerfpattern for a bend-limited catheter that has a non-uniform locking bendangle around the circumference of the catheter.

In FIG. 34B, for example, the keystone-shaped teeth are arranged inlongitudinally parallel sets of teeth having different tooth angles (andin this example, different tooth heights) that provide for differentiallocking bend angles, and therefore a bias bend configuration (e.g.,bending is biased more in one direction, e.g., north, than in otherdirections). In FIG. 34B, the tooth angles at the top 3403 of thetubular body have a tooth angle (e.g., about 40 degrees), which may bethe bend angle for teeth on the back side of the catheter (not shown).The middle region 3405 has a tooth angle of 73 degrees, which decreasesfor the teeth on either side of the middle row (e.g., to 70 degrees, 65degrees and 57 degrees, back to 40 degrees). The height of each toothalso decreases as the teeth move away from the line of teethcorresponding to the ‘north’ (e.g., the middle region 3405) in thepattern. The larger pitch of these middle teeth may allow the contactsurfaces of the sides to slide more, providing a larger expansion areain these teeth, and therefore greater bending (e.g., larger locking bendangle relative to the long axis of the catheter, a).

The bias bend design can be continuous the whole catheter length, it canis limited zone length, it can be spread between two zones (one moreproximal), bend limits in 2 zones can be out of phase to create an Scurves like property control. For example, FIGS. 35A-35C illustrate anexample of a catheter having multiple regions of bending limiting aroundtheir perimeter, in which at least one of these regions has non-uniformbend limiting. FIG. 35A shows a distal bend-limited region (“zone A”)3502 and a proximal bend-limited region (“Zone B”) 3505. In thisexample, the second zone 3505 has a bend-limited bias that is orientedin the north direction (e.g., up, as shown in FIG. 34A, e.g., at 180degrees if measured radially with south being 0 degrees). The proximalzone may be uniformly bend-limited or may also be non-uniformly bendlimiting.

FIG. 34B illustrates an example of a curvature profile for a cathetersimilar to that shown in FIG. 34A in which the second zone (3505′) isbiased.

FIG. 35C shows an example of two regions of a catheter including a firstregion 3505 that is non-uniformly bend-limited and a second region thatis uniformly bend-limited. In this example, the first region includesdifferent teeth angles in teeth aligning down the long axis of thecatheter, as shown. The second region also include a pattern ofinterlocking and alternating teeth, but all of these teeth having thesame tooth angle around the circumference of the catheter, as shown. Inthis example the tooth height is approximately the same for all teeth;the tooth heights in the non-uniformly bend-limited region may insteadvary, as described above.

FIGS. 36 and 37 illustrate alternative embodiments of cut-out kerfsforming a pattern of interlocking and alternating teeth extending aroundthe tubular body. For example, in FIG. 36, the height of the teethvarious around the circumference of the tubular body, which may modifythe smoothing, strength, flexibility and locking bend angle of thecatheter, as described above. In FIG. 37, the pitch 3701, 3703, 3705,3707 increases along the length (distal to proximal) of the catheter,similar to that shown in FIG. 33C.

Any of the methods (including user interfaces) described herein may beimplemented as software, hardware or firmware, and may be described as anon-transitory computer-readable storage medium storing a set ofinstructions capable of being executed by a processor (e.g., computer,tablet, smartphone, etc.), that when executed by the processor causesthe processor to control perform any of the steps, including but notlimited to: displaying, communicating with the user, analyzing,modifying parameters (including timing, frequency, intensity, etc.),determining, alerting, or the like.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

In general, any of the apparatuses and methods described herein shouldbe understood to be inclusive, but all or a sub-set of the componentsand/or steps may alternatively be exclusive, and may be expressed as“consisting of” or alternatively “consisting essentially of” the variouscomponents, steps, sub-components or sub-steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. A method of providing catheter access to a targetregion of a vessel within a patient's body, the method comprising:advancing a bend-limited catheter device over a guidewire or guidecatheter into the vessel until the distal end of the bend-limitedcatheter device is adjacent to the target region, wherein thebend-limited catheter comprises a tubular body having one or morecut-out kerfs forming a pattern of interlocking and alternating teethextending around the tubular body, wherein each tooth of theinterlocking and alternating teeth comprises a head region that is widerthan a base region, arranged so that the head regions alternate withbase regions radially around the tubular body, so that the tubular bodybends freely in a direction out of a long axis of the catheter device upto a locking radius, beyond which the tubular body does not allowfurther bending in the direction; removing the guidewire at leastpartially out of the bend-limited catheter; and advancing the proximalend of the bend-limited catheter so that the bend-limited catheter lockswithin the vessel by bending to the locking radius without moving thedistal end of the bend-limited catheter from the target region.
 2. Themethod of claim 1, further comprising positioning the guidewire or guidecatheter into the vessel.
 3. The method of claim 1, further comprisinginserting a treatment device through the bend-limited catheter to thetarget region.
 4. The method of claim 1, wherein the tubular body of thebend-limited catheter bends freely in a direction out of a long axis ofthe catheter device up to the locking radius of between 0.2 and 15 cm.5. The method of claim 1, wherein the tubular body of the bend-limitedcatheter bends freely with a lateral stiffness for a distal 10 cm of thecatheter that is less than 50 grams in a direction out of a long axis ofthe catheter device up to the locking radius.
 6. The method of claim 5,wherein the lateral stiffness of the distal 10 cm of the catheter is 150g or greater when the catheter is bent beyond the locking radius.
 7. Themethod of claim 1, further wherein the pattern of interlocking andalternating teeth and the cut-out kerf are configured so that thetubular body expands in the long axis from a compressed length to amaximally expanded length by between about 0.005 inches per every 0.1inch of the length of the pattern of interlocking and alternating teethand 0.085 inches per every 0.1 inch of the length of the pattern ofinterlocking and alternating teeth.
 8. The method of claim 1, whereinthe tubular body comprises one or more of: steel, tungsten, and Nitinol.9. The method of claim 1, wherein the pattern of interlocking andalternating teeth extends helically around the tubular body.
 10. Themethod of claim 1, further comprising compressing a sealing materialextending across the cut-out kerf when advancing the proximal end of thebend-limited catheter to bend to the locking radius.
 11. The method ofclaim 10, wherein the sealing material is laminated to the rigid tubularbody.
 12. The method of claim 1, further comprising rotating thecatheter from the proximal end to adjust the locking radius of thecatheter.
 13. The method of claim 1, further comprising anchoring thedistal end of the catheter near the target region.
 14. The method ofclaim 1, wherein the pattern of interlocking and alternating teethcomprise a plurality of keystone-shaped interlocking and alternatingteeth.
 15. A method of providing catheter access to a target region of avessel within a patient's body, the method comprising: advancing abend-limited catheter device over a guidewire or guide catheter into thevessel until the distal end of the bend-limited catheter device isadjacent to the target region, wherein the bend-limited cathetercomprises a tubular body having a first region of one or more cut-outkerfs forming a pattern of interlocking and alternating keystone-shapedteeth extending around the tubular body, wherein each tooth of theinterlocking and alternating keystone-shaped teeth comprises a headregion that is wider than a base region, arranged so that the headregions alternate with base regions radially around the tubular body, sothat the first region bends freely in a direction out of a long axis ofthe catheter device up to a locking radius, beyond which the tubularbody does not allow further bending in the direction; removing theguidewire at least partially out of the bend-limited catheter; andadvancing the proximal end of the bend-limited catheter so that thebend-limited catheter locks within the vessel by bending the firstregion to the locking radius without moving the distal end of thebend-limited catheter from the target region.
 16. The method of claim15, further comprising inserting a treatment device through thebend-limited catheter to the target region after removing the guide wireor guide catheter.
 17. The method of claim 15, wherein the first regionof the bend-limited catheter bends freely in a direction out of a longaxis of the catheter device up to the locking radius of between 0.2 and15 cm.
 18. The method of claim 15, wherein the tubular body of thebend-limited catheter bends freely with a lateral stiffness for a distal10 cm of the catheter that is less than 50 grams in a direction out of along axis of the catheter device up to the locking radius.
 19. Themethod of claim 18, wherein the lateral stiffness of the distal 10 cm ofthe catheter is 150 g or greater when the catheter is bent beyond thelocking radius.
 20. The method of claim 15, further wherein the patternof interlocking and alternating teeth and the cut-out kerf areconfigured so that the tubular body expands in the long axis from acompressed length to a maximally expanded length by between about 0.005inches per every 0.1 inch of the length of the pattern of interlockingand alternating teeth and 0.085 inches per every 0.1 inch of the lengthof the pattern of interlocking and alternating teeth.
 21. The method ofclaim 15, wherein the tubular body comprises one or more of: steel,tungsten, and Nitinol.
 22. The method of claim 15, wherein the patternof interlocking and alternating teeth extends helically around thetubular body.
 23. The method of claim 15, further comprising compressinga sealing material extending across the cut-out kerf when advancing theproximal end of the bend-limited catheter to bend to the locking radius.24. The method of claim 23, wherein the sealing material is laminated tothe rigid tubular body.
 25. The method of claim 15, further comprisingrotating the catheter from the proximal end to adjust the locking radiusof the first region.
 26. The method of claim 15, further comprisinganchoring the distal end of the catheter near the target region.
 27. Amethod of providing catheter access to a target region of a vesselwithin a patient's body, the method comprising: advancing a bend-limitedcatheter device over a guidewire or guide catheter into the vessel untilthe distal end of the bend-limited catheter device is adjacent to thetarget region, wherein the bend-limited catheter comprises a tubularbody having a first region of one or more cut-out kerfs forming apattern of interlocking and alternating teeth extending around thetubular body, wherein each tooth of the interlocking and alternatingteeth comprises a head region that is wider than a base region, arrangedso that the head regions alternate with base regions radially around thetubular body, so that the first region bends freely in a direction outof a long axis of the catheter device up to a locking radius, beyondwhich the tubular body does not allow further bending in the direction;removing the guidewire at least partially out of the bend-limitedcatheter; and advancing the proximal end of the bend-limited catheter sothat the bend-limited catheter locks within the vessel by bending thefirst region to the locking radius without moving the distal end of thebend-limited catheter from the target region, wherein the first regionof the tubular body of the bend-limited catheter bends freely with alateral stiffness for a distal 10 cm of the catheter that is less than50 grams in a direction out of a long axis of the catheter device up tothe locking radius.